diff --git a/modoboa/core/__init__.py b/modoboa/core/__init__.py
index 824c49add..8e81e7145 100644
--- a/modoboa/core/__init__.py
+++ b/modoboa/core/__init__.py
@@ -15,6 +15,7 @@ base_events = [
     "RoleChanged",
     "GetExtraRoles",
     "PasswordChange",
+    "UserCanSetRole",
 
     "UserMenuDisplay",
     "AdminMenuDisplay",
@@ -32,7 +33,9 @@ base_events = [
     "ExtraAdminContent",
 
     "ExtraUprefsRoutes",
-    "ExtraUprefsJS"
+    "ExtraUprefsJS",
+
+    "GetExtraParameters"
 ]
 
 
diff --git a/modoboa/core/exceptions.py b/modoboa/core/exceptions.py
deleted file mode 100644
index 063db7ad9..000000000
--- a/modoboa/core/exceptions.py
+++ /dev/null
@@ -1,14 +0,0 @@
-"""
-:mod:`exceptions` --- Custom exceptions of the admin. application
------------------------------------------------------------------
-"""
-
-from modoboa.lib.exceptions import ModoboaException
-
-
-class AdminError(ModoboaException):
-    """
-    Just a Custom exception to identify errors coming from the admin
-    application.
-    """
-    pass
diff --git a/modoboa/core/extensions.py b/modoboa/core/extensions.py
index 4b399bd24..ecd65de4a 100644
--- a/modoboa/core/extensions.py
+++ b/modoboa/core/extensions.py
@@ -49,6 +49,13 @@ class ExtensionsPool(object):
             self.extensions[name]["instance"] = self.extensions[name]["cls"]()
         return self.extensions[name]["instance"]
 
+    def is_extension_enabled(self, name):
+        from modoboa.core.models import Extension
+
+        if not name in self.extensions:
+            return False
+        return Extension.objects.get(name=name).enabled
+
     def get_extension_infos(self, name):
         instance = self.get_extension(name)
         if instance is None:
diff --git a/modoboa/core/models.py b/modoboa/core/models.py
index 4af548ad3..db0050044 100644
--- a/modoboa/core/models.py
+++ b/modoboa/core/models.py
@@ -17,10 +17,11 @@ from django.contrib.auth.models import (
     UserManager, Group, AbstractBaseUser, PermissionsMixin
 )
 from modoboa.lib import events, md5crypt, parameters
-from modoboa.lib.exceptions import PermDeniedException
+from modoboa.lib.exceptions import (
+    PermDeniedException, InternalError, BadRequest
+)
 from modoboa.lib.sysutils import exec_cmd
 from modoboa.core.extensions import exts_pool
-from modoboa.core.exceptions import AdminError
 
 try:
     from modoboa.lib.ldaputils import *
@@ -72,7 +73,9 @@ class User(AbstractBaseUser, PermissionsMixin):
             get_object_owner, grant_access_to_object, ungrant_access_to_object
 
         if fromuser == self:
-            raise AdminError(_("You can't delete your own account"))
+            raise PermDeniedException(
+                _("You can't delete your own account")
+            )
 
         if not fromuser.can_access(self):
             raise PermDeniedException
@@ -133,15 +136,15 @@ class User(AbstractBaseUser, PermissionsMixin):
             self.password = self._crypt_password(raw_value)
         else:
             if not ldap_available:
-                raise AdminError(
+                raise InternalError(
                     _("Failed to update password: LDAP module not installed")
                 )
 
             ab = LDAPAuthBackend()
             try:
                 ab.update_user_password(self.username, curvalue, raw_value)
-            except LDAPException, e:
-                raise AdminError(_("Failed to update password: %s" % str(e)))
+            except LDAPException as e:
+                raise InternalError(_("Failed to update password: %s" % str(e)))
         events.raiseEvent(
             "PasswordUpdated", self, raw_value, self.pk is None
         )
@@ -197,7 +200,7 @@ class User(AbstractBaseUser, PermissionsMixin):
         try:
             return self.groups.all()[0].name
         except IndexError:
-            return "SimpleUsers"
+            return "---"
 
     @property
     def enabled(self):
@@ -318,7 +321,7 @@ class User(AbstractBaseUser, PermissionsMixin):
         :param crypt_password:
         """
         if len(row) < 7:
-            raise AdminError(_("Invalid line"))
+            raise BadRequest(_("Invalid line"))
         role = row[6].strip()
         if not user.is_superuser and not role in ["SimpleUsers", "DomainAdmins"]:
             raise PermDeniedException(
@@ -327,11 +330,11 @@ class User(AbstractBaseUser, PermissionsMixin):
         self.username = row[1].strip()
         if role == "SimpleUsers":
             if (len(row) < 8 or not row[7].strip()):
-                raise AdminError(
+                raise BadRequest(
                     _("The simple user '%s' must have a valid email address" % self.username)
                 )
             if self.username != row[7].strip():
-                raise AdminError(
+                raise BadRequest(
                     _("username and email fields must not differ for '%s'" % self.username)
                 )
 
diff --git a/modoboa/core/views/admin.py b/modoboa/core/views/admin.py
index fdd377cb2..678c41caf 100644
--- a/modoboa/core/views/admin.py
+++ b/modoboa/core/views/admin.py
@@ -6,7 +6,7 @@ from django.contrib.auth.decorators import (
 )
 from modoboa.lib import parameters
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string
+    _render_to_string, render_to_json_response
 )
 from modoboa.lib.listing import get_sort_order, get_listing_page
 from modoboa.core.models import Extension, Log
@@ -24,7 +24,7 @@ def viewsettings(request, tplname='core/settings_header.html'):
 @login_required
 @user_passes_test(lambda u: u.is_superuser)
 def viewparameters(request, tplname='core/parameters.html'):
-    return ajax_simple_response({
+    return render_to_json_response({
         "status": "ok",
         "left_selection": "parameters",
         "content": _render_to_string(request, tplname, {
@@ -42,12 +42,10 @@ def saveparameters(request):
             form.save()
             form.to_django_settings()
             continue
-        return ajax_simple_response({
-            "status": "ko", "prefix": form.app, "errors": form.errors
-        })
-    return ajax_simple_response(dict(
-        status="ok", respmsg=_("Parameters saved")
-    ))
+        return render_to_json_response(
+            {'form_errors': form.errors, 'prefix': form.app}, status=400
+        )
+    return render_to_json_response(_("Parameters saved"))
 
 
 @login_required
@@ -68,8 +66,7 @@ def viewextensions(request, tplname='core/extensions.html'):
             ext["selection"] = False
 
     tbl = ExtensionsTable(request, exts)
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": _render_to_string(request, tplname, {"extensions": tbl})
     })
 
@@ -91,16 +88,13 @@ def saveextensions(request):
         if not ext in found:
             ext.off()
 
-    return ajax_simple_response(dict(
-        status="ok", respmsg=_("Modifications applied.")
-    ))
+    return render_to_json_response(_("Modifications applied."))
 
 
 @login_required
 @user_passes_test(lambda u: u.is_superuser)
 def information(request, tplname="core/information.html"):
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": render_to_string(tplname, {})
     })
 
@@ -118,8 +112,7 @@ def logs(request, tplname="core/logs.html"):
         Log.objects.all().order_by("%s%s" % (sort_dir, sort_order)),
         request.GET.get("page", 1)
     )
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": render_to_string(tplname, {
             "logs": page.object_list,
         }),
diff --git a/modoboa/core/views/user.py b/modoboa/core/views/user.py
index c42054526..d3cb2e8ac 100644
--- a/modoboa/core/views/user.py
+++ b/modoboa/core/views/user.py
@@ -3,7 +3,7 @@ from django.utils.translation import ugettext as _
 from django.contrib.auth.decorators import login_required
 from modoboa.lib import events, parameters
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string
+    _render_to_string, render_to_json_response
 )
 from modoboa.lib.cryptutils import encrypt
 from modoboa.core.forms import ProfileForm
@@ -32,17 +32,11 @@ def profile(request, tplname='core/user_profile.html'):
             form.save()
             if update_password and form.cleaned_data["confirmation"] != "":
                 request.session["password"] = encrypt(form.cleaned_data["confirmation"])
-            return ajax_simple_response(dict(
-                status="ok", respmsg=_("Profile updated")
-            ))
-        return ajax_simple_response({
-            "status": "ko",
-            "errors": form.errors
-        })
+            return render_to_json_response(_("Profile updated"))
+        return render_to_json_response({'form_errors': form.errors}, status=400)
 
     form = ProfileForm(update_password, instance=request.user)
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": _render_to_string(request, tplname, {
             "form": form
         })
@@ -57,16 +51,13 @@ def preferences(request):
             if form.is_valid():
                 form.save()
                 continue
-            return ajax_simple_response({
-                "status": "ko", "prefix": form.app, "errors": form.errors
-            })
+            return render_to_json_response({
+                "prefix": form.app, "form_errors": form.errors
+            }, status=400)
 
-        return ajax_simple_response({
-            "status": "ok", "respmsg": _("Preferences saved")
-        })
+        return render_to_json_response(_("Preferences saved"))
 
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": _render_to_string(request, "core/user_preferences.html", {
             "forms": parameters.get_user_forms(request.user)
         })
diff --git a/modoboa/extensions/admin/__init__.py b/modoboa/extensions/admin/__init__.py
index 22e84f0c7..7cfd3d63a 100644
--- a/modoboa/extensions/admin/__init__.py
+++ b/modoboa/extensions/admin/__init__.py
@@ -3,14 +3,12 @@ from django.utils.translation import ugettext as _, ugettext_lazy
 from django.core.urlresolvers import reverse
 from modoboa.core.extensions import ModoExtension, exts_pool
 from modoboa.lib import parameters, events
-from modoboa.lib.exceptions import PermDeniedException
+from modoboa.lib.exceptions import PermDeniedException, BadRequest
 from modoboa.lib.emailutils import split_mailbox
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.models import (
     Domain, DomainAlias, Mailbox, Alias
 )
 
-
 admin_events = [
     "DomainCreated",
     "DomainModified",
@@ -146,7 +144,7 @@ def import_account_mailbox(user, account, row):
         try:
             domain = Domain.objects.get(name=domname)
         except Domain.DoesNotExist:
-            raise AdminError(
+            raise BadRequest(
                 _("Account import failed (%s): domain does not exist" % account.username)
             )
         if not user.can_access(domain):
diff --git a/modoboa/extensions/admin/exceptions.py b/modoboa/extensions/admin/exceptions.py
deleted file mode 100644
index d0414b27b..000000000
--- a/modoboa/extensions/admin/exceptions.py
+++ /dev/null
@@ -1,19 +0,0 @@
-# coding: utf-8
-"""
-:mod:`exceptions` --- Custom exceptions of the admin. application
------------------------------------------------------------------
-"""
-
-from modoboa.lib.exceptions import ModoboaException
-
-
-class AdminError(ModoboaException):
-    """
-    Just a Custom exception to identify errors coming from the admin
-    application.
-    """
-    pass
-
-
-class BadDestination(Exception):
-    pass
diff --git a/modoboa/extensions/admin/forms/account.py b/modoboa/extensions/admin/forms/account.py
index bcbc54c86..c8afb5fae 100644
--- a/modoboa/extensions/admin/forms/account.py
+++ b/modoboa/extensions/admin/forms/account.py
@@ -2,14 +2,13 @@ from django import forms
 from django.utils.translation import ugettext as _, ugettext_lazy
 from django.http import QueryDict
 from modoboa.lib import events, parameters
-from modoboa.lib.exceptions import PermDeniedException
+from modoboa.lib.exceptions import PermDeniedException, Conflict, NotFound
 from modoboa.lib.permissions import get_account_roles
 from modoboa.lib.emailutils import split_mailbox
 from modoboa.lib.formutils import (
     DomainNameField, DynamicForm, TabForms
 )
 from modoboa.core.models import User
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.models import (
     Domain, Mailbox, Alias
 )
@@ -22,7 +21,9 @@ class AccountFormGeneral(forms.ModelForm):
         choices=[('', ugettext_lazy("Choose"))],
         help_text=ugettext_lazy("What level of permission this user will have")
     )
-    password1 = forms.CharField(label=_("Password"), widget=forms.PasswordInput)
+    password1 = forms.CharField(
+        label=_("Password"), widget=forms.PasswordInput
+    )
     password2 = forms.CharField(
         label=ugettext_lazy("Confirmation"),
         widget=forms.PasswordInput,
@@ -90,7 +91,7 @@ class AccountFormGeneral(forms.ModelForm):
     def save(self, commit=True):
         account = super(AccountFormGeneral, self).save(commit=False)
         if self.user == account and not self.cleaned_data["is_active"]:
-            raise AdminError(_("You can't disable your own account"))
+            raise PermDeniedException(_("You can't disable your own account"))
         if commit:
             if "password1" in self.cleaned_data \
                and self.cleaned_data["password1"] != "":
@@ -105,14 +106,21 @@ class AccountFormMail(forms.Form, DynamicForm):
     quota = forms.IntegerField(
         label=ugettext_lazy("Quota"),
         required=False,
-        help_text=_("Quota in MB for this mailbox. Define a custom value or use domain's default one. Leave empty to define an unlimited value (not allowed for domain administrators)."),
+        help_text=_("Quota in MB for this mailbox. Define a custom value or "
+                    "use domain's default one. Leave empty to define an "
+                    "unlimited value (not allowed for domain "
+                    "administrators)."),
         widget=forms.widgets.TextInput(attrs={"class": "span1"})
     )
     quota_act = forms.BooleanField(required=False)
     aliases = forms.EmailField(
         label=ugettext_lazy("Alias(es)"),
         required=False,
-        help_text=ugettext_lazy("Alias(es) of this mailbox. Indicate only one address per input, press ENTER to add a new input. Use the '*' character to create a 'catchall' alias (ex: *@domain.tld).")
+        help_text=ugettext_lazy(
+            "Alias(es) of this mailbox. Indicate only one address per input, "
+            "press ENTER to add a new input. Use the '*' character to create "
+            "a 'catchall' alias (ex: *@domain.tld)."
+        )
     )
 
     def __init__(self, *args, **kwargs):
@@ -143,6 +151,52 @@ class AccountFormMail(forms.Form, DynamicForm):
         """Ensure lower case emails"""
         return self.cleaned_data["email"].lower()
 
+    def create_mailbox(self, user, account):
+        locpart, domname = split_mailbox(self.cleaned_data["email"])
+        try:
+            domain = Domain.objects.get(name=domname)
+        except Domain.DoesNotExist:
+            raise NotFound(_("Domain does not exist"))
+        if not user.can_access(domain):
+            raise PermDeniedException
+        try:
+            Mailbox.objects.get(address=locpart, domain=domain)
+        except Mailbox.DoesNotExist:
+            pass
+        else:
+            raise Conflict(
+                _("Mailbox %s already exists" % self.cleaned_data["email"])
+            )
+        events.raiseEvent("CanCreate", user, "mailboxes")
+        self.mb = Mailbox(address=locpart, domain=domain, user=account,
+                          use_domain_quota=self.cleaned_data["quota_act"])
+        self.mb.set_quota(self.cleaned_data["quota"], 
+                          user.has_perm("admin.add_domain"))
+        self.mb.save(creator=user)
+
+    def update_mailbox(self, user, account):
+        newaddress = None
+        if self.cleaned_data["email"] != self.mb.full_address:
+            newaddress = self.cleaned_data["email"]
+        elif account.group == "SimpleUsers" and account.username != self.mb.full_address:
+            newaddress = account.username
+        if newaddress is not None:
+            local_part, domname = split_mailbox(newaddress)
+            try:
+                domain = Domain.objects.get(name=domname)
+            except Domain.DoesNotExist:
+                raise NotFound(_("Domain does not exist"))
+            if not user.can_access(domain):
+                raise PermDeniedException
+            self.mb.rename(local_part, domain)
+
+        self.mb.use_domain_quota = self.cleaned_data["quota_act"]
+        override_rules = True \
+            if not self.mb.quota or user.has_perm("admin.add_domain") \
+            else False
+        self.mb.set_quota(self.cleaned_data["quota"], override_rules)
+        self.mb.save()
+
     def save(self, user, account):
         if self.cleaned_data["email"] == "":
             return None
@@ -151,74 +205,43 @@ class AccountFormMail(forms.Form, DynamicForm):
             self.cleaned_data["quota"] = None
 
         if not hasattr(self, "mb") or self.mb is None:
-            locpart, domname = split_mailbox(self.cleaned_data["email"])
-            try:
-                domain = Domain.objects.get(name=domname)
-            except Domain.DoesNotExist:
-                raise AdminError(_("Domain does not exist"))
-            if not user.can_access(domain):
-                raise PermDeniedException
-            try:
-                Mailbox.objects.get(address=locpart, domain=domain)
-            except Mailbox.DoesNotExist:
-                pass
-            else:
-                raise AdminError(_("Mailbox %s already exists" % self.cleaned_data["email"]))
-            events.raiseEvent("CanCreate", user, "mailboxes")
-            self.mb = Mailbox(address=locpart, domain=domain, user=account,
-                              use_domain_quota=self.cleaned_data["quota_act"])
-            self.mb.set_quota(self.cleaned_data["quota"], 
-                              user.has_perm("admin.add_domain"))
-            self.mb.save(creator=user)
+            self.create_mailbox(user, account)
         else:
-            newaddress = None
-            if self.cleaned_data["email"] != self.mb.full_address:
-                newaddress = self.cleaned_data["email"]
-            elif account.group == "SimpleUsers" and account.username != self.mb.full_address:
-                newaddress = account.username
-            if newaddress is not None:
-                local_part, domname = split_mailbox(newaddress)
-                try:
-                    domain = Domain.objects.get(name=domname)
-                except Domain.DoesNotExist:
-                    raise AdminError(_("Domain does not exist"))
-                if not user.can_access(domain):
-                    raise PermDeniedException
-                self.mb.rename(local_part, domain)
-
-            self.mb.use_domain_quota = self.cleaned_data["quota_act"]
-            override_rules = True \
-                if not self.mb.quota or user.has_perm("admin.add_domain") \
-                else False
-            self.mb.set_quota(self.cleaned_data["quota"], override_rules)
-            self.mb.save()
+            self.update_mailbox(user, account)
 
         account.email = self.cleaned_data["email"]
         account.save()
 
+        aliases = []
         for name, value in self.cleaned_data.iteritems():
             if not name.startswith("aliases"):
                 continue
             if value == "":
                 continue
-            local_part, domname = split_mailbox(value)
-            try:
-                self.mb.alias_set.get(address=local_part, domain__name=domname)
-            except Alias.DoesNotExist:
-                pass
-            else:
-                continue
-            events.raiseEvent("CanCreate", user, "mailbox_aliases")
-            al = Alias(address=local_part, enabled=account.is_active)
-            al.domain = Domain.objects.get(name=domname)
-            al.save(int_rcpts=[self.mb], creator=user)
+            aliases.append(value)
 
         for alias in self.mb.alias_set.all():
-            if len(alias.get_recipients()) >= 2:
-                continue
-            if not len(filter(lambda name: self.cleaned_data[name] == alias.full_address,
-                              self.cleaned_data.keys())):
+            if not alias.full_address in aliases:
+                if len(alias.get_recipients()) >= 2:
+                    continue
                 alias.delete()
+            else:
+                aliases.remove(alias.full_address)
+        if aliases:
+            events.raiseEvent(
+                "CanCreate", user, "mailbox_aliases", len(aliases)
+            )
+            for alias in aliases:
+                local_part, domname = split_mailbox(alias)
+                try:
+                    self.mb.alias_set.get(address=local_part, domain__name=domname)
+                except Alias.DoesNotExist:
+                    pass
+                else:
+                    continue
+                al = Alias(address=local_part, enabled=account.is_active)
+                al.domain = Domain.objects.get(name=domname)
+                al.save(int_rcpts=[self.mb], creator=user)
 
         return self.mb
 
diff --git a/modoboa/extensions/admin/forms/alias.py b/modoboa/extensions/admin/forms/alias.py
index 89bfe4e68..555b98802 100644
--- a/modoboa/extensions/admin/forms/alias.py
+++ b/modoboa/extensions/admin/forms/alias.py
@@ -1,11 +1,11 @@
 from django import forms
 from django.utils.translation import ugettext as _, ugettext_lazy
 from django.http import QueryDict
+from modoboa.lib.exceptions import BadRequest, NotFound, Conflict
 from modoboa.lib.emailutils import split_mailbox
 from modoboa.lib.formutils import (
     DynamicForm
 )
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.models import (
     Domain, Mailbox, Alias
 )
@@ -14,11 +14,17 @@ from modoboa.extensions.admin.models import (
 class AliasForm(forms.ModelForm, DynamicForm):
     email = forms.EmailField(
         label=ugettext_lazy("Email address"),
-        help_text=ugettext_lazy("The distribution list address. Use the '*' character to create a 'catchall' address (ex: *@domain.tld).")
+        help_text=ugettext_lazy(
+            "The distribution list address. Use the '*' character to create a "
+            "'catchall' address (ex: *@domain.tld)."
+        )
     )
     recipients = forms.EmailField(
         label=ugettext_lazy("Recipients"), required=False,
-        help_text=ugettext_lazy("Mailbox(es) this alias will point to. Indicate only one address per input, press ENTER to add a new input.")
+        help_text=ugettext_lazy(
+            "Mailbox(es) this alias will point to. Indicate only one address "
+            "per input, press ENTER to add a new input."
+        )
     )
 
     class Meta:
@@ -58,7 +64,9 @@ class AliasForm(forms.ModelForm, DynamicForm):
         except Domain.DoesNotExist:
             raise forms.ValidationError(_("Domain does not exist"))
         if not self.user.can_access(domain):
-            raise forms.ValidationError(_("You don't have access to this domain"))
+            raise forms.ValidationError(
+                _("You don't have access to this domain")
+            )
         return self.cleaned_data["email"]
 
     def set_recipients(self):
@@ -78,7 +86,9 @@ class AliasForm(forms.ModelForm, DynamicForm):
                 continue
             local_part, domname = split_mailbox(v)
             if domname is None:
-                raise AdminError("%s %s" % (_("Invalid mailbox"), v))
+                raise BadRequest(
+                    u"%s %s" % (_("Invalid mailbox"), v)
+                )
             try:
                 domain = Domain.objects.get(name=domname)
             except Domain.DoesNotExist:
@@ -94,20 +104,26 @@ class AliasForm(forms.ModelForm, DynamicForm):
                     try:
                         rcpt = Mailbox.objects.get(domain=domain, address=local_part)
                     except Mailbox.DoesNotExist:
-                        raise AdminError(_("Local recipient %s not found" % v))
+                        raise NotFound(
+                            _("Local recipient %s not found" % v)
+                        )
                 if rcpt in self.int_rcpts:
-                    raise AdminError(_("Recipient %s already present" % v))
+                    raise Conflict(
+                        _("Recipient %s already present" % v)
+                    )
                 self.int_rcpts += [rcpt]
                 total += 1
                 continue
 
             if v in self.ext_rcpts:
-                raise AdminError(_("Recipient %s already present" % v))
+                raise Conflict(
+                    _("Recipient %s already present" % v)
+                )
             self.ext_rcpts += [v]
             total += 1
 
         if total == 0:
-            raise AdminError(_("No recipient defined"))
+            raise BadRequest(_("No recipient defined"))
 
     def save(self, commit=True):
         alias = super(AliasForm, self).save(commit=False)
diff --git a/modoboa/extensions/admin/forms/domain.py b/modoboa/extensions/admin/forms/domain.py
index 59682ae6c..c3686fdc9 100644
--- a/modoboa/extensions/admin/forms/domain.py
+++ b/modoboa/extensions/admin/forms/domain.py
@@ -2,11 +2,11 @@ from django import forms
 from django.http import QueryDict
 from django.utils.translation import ugettext as _, ugettext_lazy
 from modoboa.lib import events
+from modoboa.lib.exceptions import Conflict
 from modoboa.lib.formutils import (
     DomainNameField, YesNoField, DynamicForm, TabForms
 )
 from modoboa.core.models import User
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.models import (
     Domain, DomainAlias, Mailbox, Alias, Quota
 )
@@ -126,25 +126,29 @@ class DomainFormGeneral(forms.ModelForm, DynamicForm):
             d.save()
             Mailbox.objects.filter(domain=d, use_domain_quota=True) \
                 .update(quota=d.quota)
+            aliases = []
             for k, v in self.cleaned_data.iteritems():
                 if not k.startswith("aliases"):
                     continue
                 if v in ["", None]:
                     continue
-                try:
-                    d.domainalias_set.get(name=v)
-                except DomainAlias.DoesNotExist:
-                    pass
-                else:
-                    continue
-                events.raiseEvent("CanCreate", user, "domain_aliases")
-                al = DomainAlias(name=v, target=d, enabled=d.enabled)
-                al.save(creator=user)
-
+                aliases.append(v)
             for dalias in d.domainalias_set.all():
-                if not len(filter(lambda name: self.cleaned_data[name] == dalias.name,
-                                  self.cleaned_data.keys())):
+                if not dalias.name in aliases:
                     dalias.delete()
+                else:
+                    aliases.remove(dalias.name)
+            if aliases:
+                events.raiseEvent("CanCreate", user, "domain_aliases", len(aliases))
+                for alias in aliases:
+                    try:
+                        d.domainalias_set.get(name=alias)
+                    except DomainAlias.DoesNotExist:
+                        pass
+                    else:
+                        continue
+                    al = DomainAlias(name=alias, target=d, enabled=d.enabled)
+                    al.save(creator=user)
 
             if old_mail_homes is not None:
                 self.update_mailbox_quotas(d)
@@ -179,8 +183,11 @@ class DomainFormOptions(forms.Form):
         required=False
     )
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, user, *args, **kwargs):
         super(DomainFormOptions, self).__init__(*args, **kwargs)
+        if False in events.raiseQueryEvent('UserCanSetRole', user, 'DomainAdmins'):
+            self.fields = {}
+            return
         if args:
             if args[0].get("create_dom_admin", "no") == "yes":
                 self.fields["dom_admin_username"].required = True
@@ -192,6 +199,8 @@ class DomainFormOptions(forms.Form):
         return self.cleaned_data["dom_admin_username"]
 
     def save(self, user, domain):
+        if not self.fields:
+            return
         if self.cleaned_data["create_dom_admin"] == "no":
             return
         username = "%s@%s" % (self.cleaned_data["dom_admin_username"], domain.name)
@@ -200,7 +209,8 @@ class DomainFormOptions(forms.Form):
         except User.DoesNotExist:
             pass
         else:
-            raise AdminError(_("User '%s' already exists" % username))
+            raise Conflict(_("User '%s' already exists" % username))
+        events.raiseEvent("CanCreate", user, "mailboxes")
         da = User(username=username, email=username, is_active=True)
         da.set_password("password")
         da.save()
@@ -212,6 +222,7 @@ class DomainFormOptions(forms.Form):
         mb.save(creator=user)
 
         if self.cleaned_data["create_aliases"] == "yes":
+            events.raiseEvent("CanCreate", user, "mailbox_aliases")
             al = Alias(address="postmaster", domain=domain, enabled=True)
             al.save(int_rcpts=[mb], creator=user)
 
diff --git a/modoboa/extensions/admin/forms/forward.py b/modoboa/extensions/admin/forms/forward.py
index fa1e7a53a..9cf7eb643 100644
--- a/modoboa/extensions/admin/forms/forward.py
+++ b/modoboa/extensions/admin/forms/forward.py
@@ -1,7 +1,7 @@
 from django import forms
 from django.utils.translation import ugettext as _, ugettext_lazy
+from modoboa.lib.exceptions import BadRequest, PermDeniedException
 from modoboa.lib.emailutils import split_mailbox
-from modoboa.extensions.admin.exceptions import BadDestination
 from modoboa.extensions.admin.models import (
     Domain
 )
@@ -28,10 +28,14 @@ class ForwardForm(forms.Form):
         for d in rawdata.split(","):
             local_part, domname = split_mailbox(d)
             if not local_part or not domname or not len(domname):
-                raise BadDestination("Invalid mailbox syntax for %s" % d)
+                raise BadRequest("Invalid mailbox syntax for %s" % d)
             try:
                 Domain.objects.get(name=domname)
             except Domain.DoesNotExist:
                 self.dests += [d]
             else:
-                raise BadDestination(_("You can't define a forward to a local destination. Please ask your administrator to create an alias instead."))
+                raise PermDeniedException(
+                    _("You can't define a forward to a local destination. "
+                      "Please ask your administrator to create an alias "
+                      "instead.")
+                )
diff --git a/modoboa/extensions/admin/management/commands/handle_mailbox_operations.py b/modoboa/extensions/admin/management/commands/handle_mailbox_operations.py
index 56a5d24a1..056b4a55e 100644
--- a/modoboa/extensions/admin/management/commands/handle_mailbox_operations.py
+++ b/modoboa/extensions/admin/management/commands/handle_mailbox_operations.py
@@ -4,8 +4,8 @@ from optparse import make_option
 from django.core.management.base import BaseCommand
 from modoboa.lib import parameters
 from modoboa.lib.sysutils import exec_cmd
+from modoboa.lib.exceptions import InternalError
 from modoboa.extensions.admin import AdminConsole
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.models import MailboxOperation
 
 
@@ -83,7 +83,7 @@ class Command(BaseCommand):
                 continue
             try:
                 f(ope)
-            except (OperationError, AdminError) as e:
+            except (OperationError, InternalError) as e:
                 self.logger.critical('%s failed (reason: %s)',
                                      ope, str(e).encode('utf-8'))
             else:
diff --git a/modoboa/extensions/admin/models/alias.py b/modoboa/extensions/admin/models/alias.py
index e0ec8ca57..e8720ef5e 100644
--- a/modoboa/extensions/admin/models/alias.py
+++ b/modoboa/extensions/admin/models/alias.py
@@ -1,19 +1,23 @@
 import reversion
 from django.db import models
 from django.utils.translation import ugettext as _, ugettext_lazy
-from modoboa.lib import events
 from modoboa.lib.emailutils import split_mailbox
-from modoboa.lib.exceptions import PermDeniedException
-from modoboa.extensions.admin.exceptions import AdminError
+from modoboa.lib.exceptions import PermDeniedException, BadRequest
 from .base import AdminObject
 from .domain import Domain
 from .mailbox import Mailbox
 
 
 class Alias(AdminObject):
+    """
+    Mailbox alias.
+    """
     address = models.CharField(
         ugettext_lazy('address'), max_length=254,
-        help_text=ugettext_lazy("The alias address (without the domain part). For a 'catch-all' address, just enter an * character.")
+        help_text=ugettext_lazy(
+            "The alias address (without the domain part). For a 'catch-all' "
+            "address, just enter an * character."
+        )
     )
     domain = models.ForeignKey(Domain)
     mboxes = models.ManyToManyField(
@@ -139,12 +143,12 @@ class Alias(AdminObject):
 
         """
         if len(row) < expected_elements:
-            raise AdminError(_("Invalid line: %s" % row))
+            raise BadRequest(_("Invalid line: %s" % row))
         localpart, domname = split_mailbox(row[1].strip())
         try:
             domain = Domain.objects.get(name=domname)
         except Domain.DoesNotExist:
-            raise AdminError(_("Domain '%s' does not exist" % domname))
+            raise BadRequest(_("Domain '%s' does not exist" % domname))
         if not user.can_access(domain):
             raise PermDeniedException
         self.address = localpart
@@ -171,7 +175,7 @@ class Alias(AdminObject):
                     target = Mailbox.objects.get(address=localpart, 
                                                  domain__name=domname)
                 except Mailbox.DoesNotExist:
-                    raise AdminError(_("Local recipient %s not found" % rcpt))
+                    raise BadRequest(_("Local recipient %s not found" % rcpt))
             int_rcpts += [target]
         self.save(int_rcpts=int_rcpts, ext_rcpts=ext_rcpts, creator=user)
 
diff --git a/modoboa/extensions/admin/models/domain.py b/modoboa/extensions/admin/models/domain.py
index 3e4294070..7a0b909df 100644
--- a/modoboa/extensions/admin/models/domain.py
+++ b/modoboa/extensions/admin/models/domain.py
@@ -4,8 +4,8 @@ from django.db.models.manager import Manager
 from django.utils.translation import ugettext as _, ugettext_lazy
 from django.contrib.contenttypes import generic
 from modoboa.lib import events, parameters
+from modoboa.lib.exceptions import BadRequest
 from modoboa.core.models import User, ObjectAccess
-from modoboa.extensions.admin.exceptions import AdminError
 from .base import AdminObject
 
 
@@ -123,12 +123,12 @@ class Domain(AdminObject):
 
     def from_csv(self, user, row):
         if len(row) < 4:
-            raise AdminError(_("Invalid line"))
+            raise BadRequest(_("Invalid line"))
         self.name = row[1].strip()
         try:
             self.quota = int(row[2].strip())
         except ValueError:
-            raise AdminError(_("Invalid quota value for domain '%s'" % self.name))
+            raise BadRequest(_("Invalid quota value for domain '%s'" % self.name))
         self.enabled = (row[3].strip() == 'True')
         self.save(creator=user)
 
diff --git a/modoboa/extensions/admin/models/domain_alias.py b/modoboa/extensions/admin/models/domain_alias.py
index 3d087dc11..382ba74e3 100644
--- a/modoboa/extensions/admin/models/domain_alias.py
+++ b/modoboa/extensions/admin/models/domain_alias.py
@@ -1,8 +1,7 @@
 import reversion
 from django.db import models
 from django.utils.translation import ugettext as _, ugettext_lazy
-from modoboa.lib import events
-from modoboa.extensions.admin.exceptions import AdminError
+from modoboa.lib.exceptions import BadRequest
 from .base import AdminObject
 from .domain import Domain
 
@@ -37,13 +36,13 @@ class DomainAlias(AdminObject):
         :param row: a list containing the alias definition
         """
         if len(row) < 4:
-            raise AdminError(_("Invalid line"))
+            raise BadRequest(_("Invalid line"))
         self.name = row[1].strip()
         domname = row[2].strip()
         try:
             self.target = Domain.objects.get(name=domname)
         except Domain.DoesNotExist:
-            raise AdminError(_("Unknown domain %s" % domname))
+            raise BadRequest(_("Unknown domain %s" % domname))
         self.enabled = row[3].strip() == 'True'
         self.save(creator=user)
 
diff --git a/modoboa/extensions/admin/models/mailbox.py b/modoboa/extensions/admin/models/mailbox.py
index ab1da3584..a16e478a0 100644
--- a/modoboa/extensions/admin/models/mailbox.py
+++ b/modoboa/extensions/admin/models/mailbox.py
@@ -9,9 +9,9 @@ from django.utils.translation import ugettext as _, ugettext_lazy
 from django.db.models.signals import pre_delete
 from django.dispatch import receiver
 from modoboa.lib import parameters, events
+from modoboa.lib.exceptions import BadRequest, InternalError
 from modoboa.lib.sysutils import exec_cmd
 from modoboa.core.models import User
-from modoboa.extensions.admin.exceptions import AdminError
 from .base import AdminObject
 from .domain import Domain
 
@@ -110,7 +110,7 @@ class Mailbox(AdminObject):
                 "doveadm user %s -f home" % self.full_address, **options
             ) 
             if code:
-                raise AdminError(_("Failed to retrieve mailbox location (%s)" % output))
+                raise InternalError(_("Failed to retrieve mailbox location (%s)" % output))
             self.__mail_home = output.strip()
         return self.__mail_home
 
@@ -158,13 +158,13 @@ class Mailbox(AdminObject):
             else:
                 self.quota = 0
         elif int(value) > self.domain.quota and not override_rules:
-            raise AdminError(
+            raise BadRequest(
                 _("Quota is greater than the allowed domain's limit (%dM)" % self.domain.quota)
             )
         else:
             self.quota = value
         if not self.quota and self.domain.quota and not override_rules:
-            raise AdminError(_("A quota is required"))
+            raise BadRequest(_("A quota is required"))
 
     def get_quota(self):
         """Get quota limit.
diff --git a/modoboa/extensions/admin/static/admin/js/admin.js b/modoboa/extensions/admin/static/admin/js/admin.js
index 87f1a51c3..313bc332e 100644
--- a/modoboa/extensions/admin/static/admin/js/admin.js
+++ b/modoboa/extensions/admin/static/admin/js/admin.js
@@ -143,8 +143,8 @@ Admin.prototype = {
 
     reload_listing: function(data) {
         this.navobj.update(true);
-        if (data.respmsg) {
-            $("body").notify("success", data.respmsg, 2000);
+        if (data) {
+            $("body").notify("success", data, 2000);
         }
     }
 };
@@ -180,11 +180,7 @@ Domains.prototype = {
             checkboxes: deloptions,
             success_cb: $.proxy(this.reload_listing, this)
         });
-        $("a[name=delrelaydomain]").confirm({
-            question: function() { return this.$element.attr('title'); },
-            method: "DELETE",
-            success_cb: $.proxy(this.reload_listing, this)
-        });
+        $(document).trigger('domain_listing_refresh');
     },
 
     change_inputs_state: function(value) {
@@ -239,7 +235,7 @@ Domains.prototype = {
                 1: this.optionsform_prefill
             },
             error_callbacks: {
-                1: this.generalform_init,
+                //1: this.generalform_init,
                 2: $.proxy(this.optionsform_init, this)
             },
             success_callback: $.proxy(this.reload_listing, this)
@@ -397,11 +393,7 @@ Identities.prototype = {
         $("#wizard").cwizard({
             formid: "newaccount_form",
             transition_callbacks: {
-                1: this.mailform_prefill
-            },
-            error_callbacks: {
-                1: $.proxy(this.generalform_init, this),
-                2: $.proxy(this.mailform_init, this)
+                2: this.mailform_prefill
             },
             success_callback: $.proxy(this.reload_listing, this)
         });
@@ -409,10 +401,9 @@ Identities.prototype = {
 
     editaccount_cb: function() {
         this.accountform_init();
-        $('.submit').one('click', $.proxy(function(e) {
+        $('.submit').on('click', $.proxy(function(e) {
             simple_ajax_form_post(e, {
                 formid: "accountform",
-                error_cb: $.proxy(this.editaccount_cb, this),
                 reload_on_success: false,
                 success_cb: $.proxy(this.reload_listing, this)
             });
@@ -425,10 +416,9 @@ Identities.prototype = {
             choices: get_domains_list
         });
         $("#id_recipients").dynamic_input();
-        $(".submit").one('click', $.proxy(function(e) {
+        $(".submit").on('click', $.proxy(function(e) {
             simple_ajax_form_post(e, {
                 formid: "aliasform",
-                error_cb: $.proxy(this.aliasform_cb, this),
                 reload_on_success: false,
                 success_cb: $.proxy(this.reload_listing, this)
             });
diff --git a/modoboa/extensions/admin/templates/admin/dlistform.html b/modoboa/extensions/admin/templates/admin/aliasform.html
similarity index 67%
rename from modoboa/extensions/admin/templates/admin/dlistform.html
rename to modoboa/extensions/admin/templates/admin/aliasform.html
index 20f3cd51d..6a13e26c9 100644
--- a/modoboa/extensions/admin/templates/admin/dlistform.html
+++ b/modoboa/extensions/admin/templates/admin/aliasform.html
@@ -1,5 +1,4 @@
-{% extends "common/generic_modal_form.html" %}
-{% load lib_tags %}
+{% extends "common/generic_modal_form.html" %}{% load lib_tags %}
 {% block formbody %}
 {% render_field form.email %}
 {% render_fields_group form "recipients" %}
diff --git a/modoboa/extensions/admin/templates/admin/domain_options_form.html b/modoboa/extensions/admin/templates/admin/domain_options_form.html
index c8acba112..b1c050f85 100644
--- a/modoboa/extensions/admin/templates/admin/domain_options_form.html
+++ b/modoboa/extensions/admin/templates/admin/domain_options_form.html
@@ -1,4 +1,5 @@
-{% load i18n lib_tags %}
+{% load i18n lib_tags %}{% if form.fields %}
 {% render_field form.create_dom_admin %}
 {% render_field_appended form.dom_admin_username "@" %}
 {% render_field form.create_aliases %}
+{% else %}<div class="alert alert-warning">{% trans "You can't create a new domain administrator" %}</div>{% endif %}
diff --git a/modoboa/extensions/admin/tests/account.py b/modoboa/extensions/admin/tests/account.py
index fa8773bc1..6f316eb17 100644
--- a/modoboa/extensions/admin/tests/account.py
+++ b/modoboa/extensions/admin/tests/account.py
@@ -19,9 +19,9 @@ class AccountTestCase(ModoTestCase):
             username="tester@test.com", first_name="Tester", last_name="Toto",
             password1="toto", password2="toto", role="SimpleUsers",
             quota_act=True,
-            is_active=True, email="tester@test.com", stepid=2
+            is_active=True, email="tester@test.com", stepid='step2'
         )
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.newaccount"),
             values
         )
@@ -39,26 +39,26 @@ class AccountTestCase(ModoTestCase):
         self.assertEqual(mb.domain.mailbox_count, 3)
 
         values["username"] = "pouet@test.com"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[account.id]),
             values
         )
         mb = Mailbox.objects.get(pk=mb.id)
         self.assertEqual(mb.full_address, "pouet@test.com")
-        self.check_ajax_get(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.delaccount",
                     args=[account.id]),
             {}
         )
 
-    def _set_quota(self, email, value, expected_status="ok"):
+    def _set_quota(self, email, value, expected_status=200):
         account = User.objects.get(username=email)
         values = {
             "username": email, "role": "SimpleUsers", "quota_act": False,
             "is_active": True, "quota": value, "email": email
         }
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[account.id]),
             values, status=expected_status
@@ -70,7 +70,7 @@ class AccountTestCase(ModoTestCase):
     def test_set_nul_quota_as_domainadmin(self):
         self.clt.logout()
         self.assertTrue(self.clt.login(username="admin@test.com", password="toto"))
-        self._set_quota("user@test.com", 0, "ko")
+        self._set_quota("user@test.com", 0, 424)
         self.clt.logout()
         self.assertTrue(self.clt.login(username="admin@test2.com", password="toto"))
         self._set_quota("user@test2.com", 0)
@@ -92,25 +92,24 @@ class PermissionsTestCase(ModoTestCase):
         self.clt.logout()
 
     def test_domain_admins(self):
-        self.values["role"] = "DomainAdmins"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[self.user.id]),
             self.values
         )
-        self.assertEqual(self.user.group == "DomainAdmins", True)
+        self.assertEqual(self.user.group, "DomainAdmins")
 
         self.values["role"] = "SimpleUsers"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[self.user.id]),
             self.values
         )
-        self.assertEqual(self.user.group == 'DomainAdmins', False)
+        self.assertNotEqual(self.user.group, 'DomainAdmins')
 
     def test_superusers(self):
         self.values["role"] = "SuperAdmins"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[self.user.id]),
             self.values
@@ -118,7 +117,7 @@ class PermissionsTestCase(ModoTestCase):
         self.assertEqual(User.objects.get(username="user@test.com").is_superuser, True)
 
         self.values["role"] = "SimpleUsers"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[self.user.id]),
             self.values
@@ -135,7 +134,7 @@ class PermissionsTestCase(ModoTestCase):
             password1="", password2="",
             quota=10, is_active=True, email="admin@test.com"
         )
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[admin.id]),
             values
@@ -144,7 +143,7 @@ class PermissionsTestCase(ModoTestCase):
         self.assertEqual(admin.can_access(Domain.objects.get(name="test.com")), True)
 
         values["role"] = "SuperAdmins"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[admin.id]),
             values
@@ -178,25 +177,23 @@ class PermissionsTestCase(ModoTestCase):
             username="superadmin2@test.com", first_name="Super",
             last_name="Admin", password1="toto", password2="toto",
             role="SuperAdmins", is_active=True,
-            email="superadmin2@test.com", stepid=2
+            email="superadmin2@test.com", stepid='step2'
         )
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.newaccount"),
             values
         )
         account = User.objects.get(username="superadmin2@test.com")
         self.clt.logout()
         self.clt.login(username="admin@test.com", password="toto")
-        self.check_ajax_get(
+        self.ajax_get(
             reverse("modoboa.extensions.admin.views.identity.delaccount",
                     args=[account.id]),
-            {},
-            status="ko", respmsg="Permission denied"
+            {}, 403
         )
-        self.check_ajax_get(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.delaccount",
-                    args=[account.id]), {},
-            status="ko", respmsg="Permission denied"
+                    args=[account.id]), {}, 403
         )
 
     def test_domainadmin_dlist_local_domain_not_owned(self):
@@ -208,6 +205,6 @@ class PermissionsTestCase(ModoTestCase):
             recipients_1="user@test2.com",
             enabled=True
         )
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.newdlist"), values
         )
diff --git a/modoboa/extensions/admin/tests/alias.py b/modoboa/extensions/admin/tests/alias.py
index 1cb9a277d..ff6fbc840 100644
--- a/modoboa/extensions/admin/tests/alias.py
+++ b/modoboa/extensions/admin/tests/alias.py
@@ -21,7 +21,7 @@ class AliasTestCase(ModoTestCase):
             is_active=user.is_active, email="user@test.com",
             aliases="toto@test.com", aliases_1="titi@test.com"
         )
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[user.id]),
             values
@@ -29,7 +29,7 @@ class AliasTestCase(ModoTestCase):
         self.assertEqual(user.mailbox_set.all()[0].alias_set.count(), 2)
 
         del values["aliases_1"]
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.editaccount",
                     args=[user.id]),
             values
@@ -42,7 +42,7 @@ class AliasTestCase(ModoTestCase):
                       recipients_1="admin@test.com",
                       recipients_2="ext@titi.com",
                       enabled=True)
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.newdlist"), values
         )
         user = User.objects.get(username="user@test.com")
@@ -53,14 +53,14 @@ class AliasTestCase(ModoTestCase):
         dlist = Alias.objects.get(address="all", domain__name="test.com")
         self.assertEqual(len(dlist.get_recipients()), 3)
         del values["recipients_1"]
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.editalias",
                     args=[dlist.id]),
             values
         )
         self.assertEqual(dlist.get_recipients_count(), 2)
 
-        self.check_ajax_get(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.delalias") + "?selection=%d" \
                 % dlist.id, {}
         )
@@ -69,21 +69,21 @@ class AliasTestCase(ModoTestCase):
 
     def test_forward(self):
         values = dict(email="forward2@test.com", recipients="rcpt@dest.com")
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.newforward"), values
         )
         fwd = Alias.objects.get(address="forward2", domain__name="test.com")
         self.assertEqual(fwd.get_recipients_count(), 1)
 
         values["recipients"] = "rcpt2@dest.com"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.editalias",
                     args=[fwd.id]),
             values
         )
         self.assertEqual(fwd.get_recipients_count(), 1)
 
-        self.check_ajax_get(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.delalias") + "?selection=%d" \
                 % fwd.id, {}
         )
@@ -92,7 +92,7 @@ class AliasTestCase(ModoTestCase):
 
     def test_forward_and_local_copies(self):
         values = dict(email="user@test.com", recipients="rcpt@dest.com")
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.newforward"), values
         )
         fwd = Alias.objects.get(address="user", domain__name="test.com")
@@ -100,7 +100,7 @@ class AliasTestCase(ModoTestCase):
 
         values["recipients"] = "rcpt@dest.com"
         values["recipients_1"] = "user@test.com"
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.alias.editalias", args=[fwd.id]),
             values
         )
diff --git a/modoboa/extensions/admin/tests/domain.py b/modoboa/extensions/admin/tests/domain.py
index 234e0f117..929afd3c8 100644
--- a/modoboa/extensions/admin/tests/domain.py
+++ b/modoboa/extensions/admin/tests/domain.py
@@ -19,9 +19,9 @@ class DomainTestCase(ModoTestCase):
         """
         values = {
             "name": "pouet.com", "quota": 100, "create_dom_admin": "no",
-            "stepid": 2
+            "stepid": 'step2'
         }
-        self.check_ajax_post(reverse("modoboa.extensions.admin.views.domain.newdomain"), values)
+        self.ajax_post(reverse("modoboa.extensions.admin.views.domain.newdomain"), values)
         dom = Domain.objects.get(name="pouet.com")
         self.assertEqual(dom.name, "pouet.com")
         self.assertEqual(dom.quota, 100)
@@ -35,9 +35,9 @@ class DomainTestCase(ModoTestCase):
         values = {
             "name": "pouet.com", "quota": 100, "create_dom_admin": "yes",
             "dom_admin_username": "toto", "create_aliases": "yes",
-            "stepid": 2
+            "stepid": 'step2'
         }
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.domain.newdomain"),
             values
         )
@@ -53,9 +53,9 @@ class DomainTestCase(ModoTestCase):
         values = {
             "name": "pouet.com", "quota": 0, "create_dom_admin": "yes",
             "dom_admin_username": "toto", "create_aliases": "yes",
-            "stepid": 2
+            "stepid": 'step2'
         }
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.domain.newdomain"),
             values
         )
@@ -75,7 +75,7 @@ class DomainTestCase(ModoTestCase):
             "name": "pouet.com", "quota": 100, "enabled": True
         }
         dom = Domain.objects.get(name="test.com")
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.domain.editdomain",
                     args=[dom.id]), 
             values
@@ -88,7 +88,7 @@ class DomainTestCase(ModoTestCase):
         """Test the removal of a domain
         """
         dom = Domain.objects.get(name="test.com")
-        self.check_ajax_get(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.domain.deldomain",
                     args=[dom.id]),
             {}
diff --git a/modoboa/extensions/admin/tests/domain_alias.py b/modoboa/extensions/admin/tests/domain_alias.py
index d79e2a645..9930d0d16 100644
--- a/modoboa/extensions/admin/tests/domain_alias.py
+++ b/modoboa/extensions/admin/tests/domain_alias.py
@@ -31,7 +31,7 @@ class DomainAliasTestCase(ModoTestCase):
         dom = Domain.objects.get(name="test.com")
         values = dict(name=dom.name, quota=dom.quota, enabled=dom.enabled,
                       aliases="domalias.net", aliases_1="domalias.com")
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.domain.editdomain",
                     args=[dom.id]),
             values
@@ -39,7 +39,7 @@ class DomainAliasTestCase(ModoTestCase):
         self.assertEqual(dom.domainalias_set.count(), 2)
 
         del values["aliases_1"]
-        self.check_ajax_post(
+        self.ajax_post(
             reverse("modoboa.extensions.admin.views.domain.editdomain",
                     args=[dom.id]),
             values
diff --git a/modoboa/extensions/admin/views/alias.py b/modoboa/extensions/admin/views/alias.py
index b03c32fd3..c8410615f 100644
--- a/modoboa/extensions/admin/views/alias.py
+++ b/modoboa/extensions/admin/views/alias.py
@@ -6,59 +6,50 @@ from django.contrib.auth.decorators import (
     login_required, permission_required
 )
 from modoboa.lib import events
-from modoboa.lib.webutils import ajax_response, ajax_simple_response
-from modoboa.lib.exceptions import PermDeniedException
-from modoboa.extensions.admin.exceptions import AdminError
+from modoboa.lib.webutils import render_to_json_response
+from modoboa.lib.exceptions import PermDeniedException, Conflict
 from modoboa.extensions.admin.forms import AliasForm
 from modoboa.extensions.admin.models import Alias
 
 
-def _validate_alias(request, form, successmsg, tplname, commonctx, callback=None):
+def _validate_alias(request, form, successmsg, callback=None):
     """Alias validation
 
     Common function shared between creation and modification actions.
     """
-    error = None
     if form.is_valid():
         form.set_recipients()
         try:
             alias = form.save()
         except IntegrityError:
-            raise AdminError(_("Alias with this name already exists"))
+            raise Conflict(_("Alias with this name already exists"))
         if callback:
             callback(request.user, alias)
-        return ajax_simple_response({"status": "ok", "respmsg": successmsg})
+        return render_to_json_response(successmsg)
 
-    if "targets" in request.POST:
-        targets = request.POST.getlist("targets")
-        commonctx["targets"] = targets[:-1]
-
-    commonctx["form"] = form
-    commonctx["error"] = error
-    return ajax_response(request, status="ko", template=tplname, **commonctx)
+    return render_to_json_response({'form_errors': form.errors}, status=400)
 
 
 def _new_alias(request, title, action, successmsg,
-               tplname="common/generic_modal_form.html"):
+               tplname="admin/aliasform.html"):
     events.raiseEvent("CanCreate", request.user, "mailbox_aliases")
-    ctx = {
-        "title": title,
-        "action": action,
-        "formid": "aliasform",
-        "action_label": _("Create"),
-        "action_classes": "submit"
-    }
     if request.method == "POST":
         def callback(user, alias):
             alias.post_create(user)
 
         form = AliasForm(request.user, request.POST)
         return _validate_alias(
-            request, form, successmsg, tplname, ctx, callback
+            request, form, successmsg, callback
         )
 
-    form = AliasForm(request.user)
-    ctx["form"] = form
+    ctx = {
+        "title": title,
+        "action": action,
+        "formid": "aliasform",
+        "action_label": _("Create"),
+        "action_classes": "submit",
+        "form": AliasForm(request.user)
+    }
     return render(request, tplname, ctx)
 
 
@@ -94,29 +85,29 @@ def newforward(request):
 
 @login_required
 @permission_required("admin.change_alias")
-def editalias(request, alid, tplname="common/generic_modal_form.html"):
+@transaction.commit_on_success
+def editalias(request, alid, tplname="admin/aliasform.html"):
     alias = Alias.objects.get(pk=alid)
     if not request.user.can_access(alias):
         raise PermDeniedException
-    ctx = dict(
-        action=reverse(editalias, args=[alias.id]),
-        formid="aliasform",
-        title=alias.full_address,
-        action_label=_("Update"),
-        action_classes="submit"
-    )
-    if len(alias.get_recipients()) >= 2:
-        successmsg = _("Distribution list modified")
-    elif alias.extmboxes != "":
-        successmsg = _("Forward modified")
-    else:
-        successmsg = _("Alias modified")
     if request.method == "POST":
+        if len(alias.get_recipients()) >= 2:
+            successmsg = _("Distribution list modified")
+        elif alias.extmboxes != "":
+            successmsg = _("Forward modified")
+        else:
+            successmsg = _("Alias modified")
         form = AliasForm(request.user, request.POST, instance=alias)
-        return _validate_alias(request, form, successmsg, tplname, ctx)
+        return _validate_alias(request, form, successmsg)
 
-    form = AliasForm(request.user, instance=alias)
-    ctx["form"] = form
+    ctx = {
+        'action': reverse(editalias, args=[alias.id]),
+        'formid': 'aliasform',
+        'title': alias.full_address,
+        'action_label': _('Update'),
+        'action_classes': 'submit',
+        'form': AliasForm(request.user, instance=alias)
+    }
     return render(request, tplname, ctx)
 
 
@@ -141,4 +132,4 @@ def delalias(request):
         alias.delete()
 
     msg = ungettext(msg, msgs, len(selection))
-    return ajax_simple_response({"status": "ok", "respmsg": msg})
+    return render_to_json_response(msg)
diff --git a/modoboa/extensions/admin/views/domain.py b/modoboa/extensions/admin/views/domain.py
index 812cc4928..29b43132c 100644
--- a/modoboa/extensions/admin/views/domain.py
+++ b/modoboa/extensions/admin/views/domain.py
@@ -2,7 +2,6 @@ from django.http import HttpResponseRedirect
 from django.utils.translation import ugettext as _, ungettext
 from django.core.urlresolvers import reverse
 from django.db import transaction
-from django.db.models import Q
 from django.shortcuts import render
 from django.views.decorators.csrf import ensure_csrf_cookie
 from django.contrib.auth.decorators import (
@@ -10,13 +9,15 @@ from django.contrib.auth.decorators import (
 )
 from modoboa.lib import parameters, events
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string
+    ajax_simple_response, _render_to_string,
+    render_to_json_response
 )
 from modoboa.lib.formutils import CreationWizard
-from modoboa.lib.exceptions import PermDeniedException
+from modoboa.lib.exceptions import (
+    ModoboaException, PermDeniedException, BadRequest
+)
 from modoboa.lib.templatetags.lib_tags import pagination_bar
 from modoboa.extensions.admin.lib import get_sort_order, get_listing_page
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.models import Domain, Mailbox
 from modoboa.extensions.admin.forms import (
     DomainForm, DomainFormGeneral, DomainFormOptions
@@ -90,50 +91,49 @@ def domains_list(request):
 def newdomain(request, tplname="common/wizard_forms.html"):
     events.raiseEvent("CanCreate", request.user, "domains")
 
-    def newdomain_cb(steps):
-        genform = steps[0]["form"]
-        genform.is_valid()
-        domain = genform.save(request.user)
-        domain.post_create(request.user)
-        steps[1]["form"].save(request.user, domain)
-
-    commonctx = {"title": _("New domain"),
-                 "action_label": _("Create"),
-                 "action_classes": "submit",
-                 "action": reverse(newdomain),
-                 "formid": "domform"}
-    cwizard = CreationWizard(newdomain_cb)
+    cwizard = CreationWizard()
     cwizard.add_step(DomainFormGeneral, _("General"),
                      [dict(classes="btn-inverse next", label=_("Next"))],
                      formtpl="admin/domain_general_form.html")
-    cwizard.add_step(DomainFormOptions, _("Options"),
-                     [dict(classes="btn-primary submit", label=_("Create")),
-                      dict(classes="btn-inverse prev", label=_("Previous"))],
-                     formtpl="admin/domain_options_form.html")
+    cwizard.add_step(
+        DomainFormOptions, _("Options"),
+        [dict(classes="btn-primary submit", label=_("Create")),
+         dict(classes="btn-inverse prev", label=_("Previous"))],
+        formtpl="admin/domain_options_form.html",
+        new_args=[request.user]
+    )
 
     if request.method == "POST":
         retcode, data = cwizard.validate_step(request)
         if retcode == -1:
-            raise AdminError(data)
+            raise BadRequest(data)
         if retcode == 1:
-            return ajax_simple_response(dict(
-                status="ok", title=cwizard.get_title(data + 1), stepid=data
-            ))
-        if retcode == 2:
-            return ajax_simple_response(
-                dict(status="ok", respmsg=_("Domain created"))
+            return render_to_json_response(
+                {'title': cwizard.get_title(data + 1), 'stepid': data}
             )
+        if retcode == 2:
+            genform = cwizard.steps[0]["form"]
+            domain = genform.save(request.user)
+            domain.post_create(request.user)
+            try:
+                cwizard.steps[1]["form"].save(request.user, domain)
+            except ModoboaException as e:
+                transaction.rollback()
+                raise
+            return render_to_json_response(_("Domain created"))
+        return render_to_json_response({
+            'stepid': data, 'form_errors': cwizard.errors
+        }, status=400)
 
-        from modoboa.lib.templatetags.lib_tags import render_form
-        return ajax_simple_response(dict(
-            status="ko", stepid=data,
-            form=render_form(cwizard.steps[data]["form"])
-        ))
-
+    ctx = {"title": _("New domain"),
+           "action_label": _("Create"),
+           "action_classes": "submit",
+           "action": reverse(newdomain),
+           "formid": "domform"}
     cwizard.create_forms()
-    commonctx.update(steps=cwizard.steps)
-    commonctx.update(subtitle="1. %s" % cwizard.steps[0]['title'])
-    return render(request, tplname, commonctx)
+    ctx.update(steps=cwizard.steps)
+    ctx.update(subtitle="1. %s" % cwizard.steps[0]['title'])
+    return render(request, tplname, ctx)
 
 
 @login_required
@@ -144,44 +144,32 @@ def editdomain(request, dom_id, tplname="admin/editdomainform.html"):
     if not request.user.can_access(domain):
         raise PermDeniedException
 
+    instances = dict(general=domain)
+    events.raiseEvent("FillDomainInstances", request.user, domain, instances)
+    if request.method == "POST":
+        domain.oldname = domain.name
+        form = DomainForm(request.user, request.POST, instances=instances)
+        if form.is_valid():
+            form.save(request.user)
+            events.raiseEvent("DomainModified", domain)
+            return render_to_json_response(_("Domain modified"))
+        return render_to_json_response({
+            'form_errors': form.errors
+        }, status=400)
+
     domadmins = [u for u in domain.admins
                  if request.user.can_access(u) and not u.is_superuser]
     if not request.user.is_superuser:
         domadmins = [u for u in domadmins if u.group == "DomainAdmins"]
-
-    instances = dict(general=domain)
-    events.raiseEvent("FillDomainInstances", request.user, domain, instances)
-
-    commonctx = {"title": domain.name,
-                 "action_label": _("Update"),
-                 "action_classes": "submit",
-                 "action": reverse(editdomain, args=[dom_id]),
-                 "formid": "domform",
-                 "domain": domain}
-    if request.method == "POST":
-        error = None
-        domain.oldname = domain.name
-        form = DomainForm(request.user, request.POST, instances=instances)
-        if form.is_valid():
-            try:
-                form.save(request.user)
-            except AdminError, e:
-                error = str(e)
-            else:
-                events.raiseEvent("DomainModified", domain)
-                return ajax_simple_response({
-                    "status": "ok", "respmsg": _("Domain modified")
-                })
-
-        commonctx["tabs"] = form
-        return ajax_simple_response({
-            "status": "ko", "respmsg": error,
-            "content": _render_to_string(request, tplname, commonctx)
-        })
-
-    commonctx["tabs"] = DomainForm(request.user, instances=instances)
-    commonctx["domadmins"] = domadmins
-    return render(request, tplname, commonctx)
+    ctx = {"title": domain.name,
+           "action_label": _("Update"),
+           "action_classes": "submit",
+           "action": reverse(editdomain, args=[dom_id]),
+           "formid": "domform",
+           "domain": domain,
+           "tabs": DomainForm(request.user, instances=instances),
+           "domadmins": domadmins}
+    return render(request, tplname, ctx)
 
 
 @login_required
@@ -198,8 +186,8 @@ def deldomain(request, dom_id):
     if not request.user.can_access(dom):
         raise PermDeniedException
     if mb and mb.domain == dom:
-        raise AdminError(_("You can't delete your own domain"))
+        raise PermDeniedException(_("You can't delete your own domain"))
     dom.delete(request.user, keepdir)
 
     msg = ungettext("Domain deleted", "Domains deleted", 1)
-    return ajax_simple_response({"status": "ok", "respmsg": msg})
+    return render_to_json_response(msg)
diff --git a/modoboa/extensions/admin/views/identity.py b/modoboa/extensions/admin/views/identity.py
index a2f1e1bc4..7ab550a68 100644
--- a/modoboa/extensions/admin/views/identity.py
+++ b/modoboa/extensions/admin/views/identity.py
@@ -7,9 +7,12 @@ from django.contrib.auth.decorators import (
 )
 from django.views.decorators.csrf import ensure_csrf_cookie
 from modoboa.lib import parameters, events
-from modoboa.lib.exceptions import PermDeniedException
+from modoboa.lib.exceptions import (
+    ModoboaException, PermDeniedException, BadRequest
+)
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string, ajax_response
+    ajax_simple_response, _render_to_string,
+    render_to_json_response
 )
 from modoboa.lib.formutils import CreationWizard
 from modoboa.lib.templatetags.lib_tags import pagination_bar
@@ -18,7 +21,6 @@ from modoboa.extensions.admin.models import Mailbox, Domain
 from modoboa.extensions.admin.lib import (
     get_sort_order, get_listing_page, get_identities
 )
-from modoboa.extensions.admin.exceptions import AdminError
 from modoboa.extensions.admin.forms import (
     AccountForm, AccountFormGeneral, AccountFormMail
 )
@@ -99,7 +101,7 @@ def list_quotas(request, tplname="admin/quotas.html"):
             order_by=["%s%s" % (sort_dir, sort_order)]
         )
     else:
-        raise AdminError(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     page = get_listing_page(mboxes, request.GET.get("page", 1))
     return ajax_simple_response({
         "status": "ok",
@@ -115,35 +117,7 @@ def list_quotas(request, tplname="admin/quotas.html"):
 @permission_required("core.add_user")
 @transaction.commit_on_success
 def newaccount(request, tplname='common/wizard_forms.html'):
-    def create_account(steps):
-        """Account creation callback
-
-        Called when all creation steps have been validated.
-
-        :param steps: the steps data
-        """
-        genform = steps[0]["form"]
-        genform.is_valid()
-        account = genform.save()
-        account.post_create(request.user)
-
-        mailform = steps[1]["form"]
-        try:
-            mailform.save(request.user, account)
-        except AdminError:
-            # A bit uggly: transaction management doesn't work very
-            # well with nested functions. Need to wait for django 1.6
-            # and atomicity.
-            account.delete(request.user, False)
-            raise
-
-    ctx = dict(
-        title=_("New account"),
-        action=reverse(newaccount),
-        formid="newaccount_form",
-        submit_label=_("Create")
-    )
-    cwizard = CreationWizard(create_account)
+    cwizard = CreationWizard()
     cwizard.add_step(AccountFormGeneral, _("General"),
                      [dict(classes="btn-inverse next", label=_("Next"))],
                      new_args=[request.user])
@@ -155,22 +129,35 @@ def newaccount(request, tplname='common/wizard_forms.html'):
     if request.method == "POST":
         retcode, data = cwizard.validate_step(request)
         if retcode == -1:
-            raise AdminError(data)
+            raise BadRequest(data)
         if retcode == 1:
-            return ajax_simple_response(dict(
-                status="ok", title=cwizard.get_title(data + 1), stepid=data
-            ))
+            return render_to_json_response(
+                {'title': cwizard.get_title(data + 1), 'stepid': data}
+            )
         if retcode == 2:
-            return ajax_simple_response(dict(
-                status="ok", respmsg=_("Account created")
-            ))
-
-        from modoboa.lib.templatetags.lib_tags import render_form
-        return ajax_simple_response(dict(
-            status="ko", stepid=data,
-            form=render_form(cwizard.steps[data]["form"])
-        ))
+            genform = cwizard.steps[0]["form"]
+            account = genform.save()
+            try:
+                account.post_create(request.user)
+                mailform = cwizard.steps[1]["form"]
+                mailform.save(request.user, account)
+            except ModoboaException:
+                # A bit uggly: transaction management doesn't work very
+                # well with nested functions. Need to wait for django 1.6
+                # and atomicity.
+                account.delete(request.user, False)
+                raise
+            return render_to_json_response(_("Account created"))
+        return render_to_json_response({
+            'stepid': data, 'form_errors': cwizard.errors
+        }, status=400)
 
+    ctx = {
+        'title': _("New account"),
+        'action': reverse(newaccount),
+        'formid': 'newaccount_form',
+        'submit_label': _("Create")
+    }
     cwizard.create_forms()
     ctx.update(steps=cwizard.steps)
     ctx.update(subtitle="1. %s" % cwizard.steps[0]['title'])
@@ -191,14 +178,6 @@ def editaccount(request, accountid, tplname="common/tabforms.html"):
     instances = dict(general=account, mail=mb, perms=account)
     events.raiseEvent("FillAccountInstances", request.user, account, instances)
 
-    ctx = dict(
-        title=account.username,
-        formid="accountform",
-        action=reverse(editaccount, args=[accountid]),
-        action_label=_("Update"),
-        action_classes="submit"
-    )
-
     if request.method == "POST":
         classes = {}
         form = AccountForm(request.user, request.POST,
@@ -209,15 +188,17 @@ def editaccount(request, accountid, tplname="common/tabforms.html"):
             if form.is_valid(optional_only=True):
                 events.raiseEvent("AccountModified", account, form.account)
                 form.save()
-                return ajax_simple_response(
-                    dict(status="ok", respmsg=_("Account updated"))
-                )
-            transaction.rollback()
+                return render_to_json_response(_("Account updated"))
+        return render_to_json_response({'form_errors': form.errors}, status=400)
 
-        ctx["tabs"] = form
-        return ajax_response(request, status="ko", template=tplname, **ctx)
-
-    ctx["tabs"] = AccountForm(request.user, instances=instances)
+    ctx = {
+        'title': account.username,
+        'formid': 'accountform',
+        'action': reverse(editaccount, args=[accountid]),
+        'action_label': _('Update'),
+        'action_classes': 'submit',
+        'tabs': AccountForm(request.user, instances=instances)
+    }
     active_tab_id = request.GET.get("active_tab", "default")
     if active_tab_id != "default":
         ctx["tabs"].active_id = active_tab_id
@@ -229,11 +210,10 @@ def editaccount(request, accountid, tplname="common/tabforms.html"):
 @transaction.commit_on_success
 def delaccount(request, accountid):
     keepdir = True if request.POST.get("keepdir", "false") == "true" else False
-
     User.objects.get(pk=accountid).delete(request.user, keep_mb_dir=keepdir)
-
-    msg = ungettext("Account deleted", "Accounts deleted", 1)
-    return ajax_simple_response({"status": "ok", "respmsg": msg})
+    return render_to_json_response(
+        ungettext("Account deleted", "Accounts deleted", 1)
+    )
 
 
 @login_required
@@ -242,12 +222,12 @@ def remove_permission(request):
     domid = request.GET.get("domid", None)
     daid = request.GET.get("daid", None)
     if domid is None or daid is None:
-        raise AdminError(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     try:
         account = User.objects.get(pk=daid)
         domain = Domain.objects.get(pk=domid)
     except (User.DoesNotExist, Domain.DoesNotExist):
-        raise AdminError(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     if not request.user.can_access(account) or not request.user.can_access(domain):
         raise PermDeniedException
     domain.remove_admin(account)
diff --git a/modoboa/extensions/admin/views/user.py b/modoboa/extensions/admin/views/user.py
index 37fdd6d09..7c0382c41 100644
--- a/modoboa/extensions/admin/views/user.py
+++ b/modoboa/extensions/admin/views/user.py
@@ -2,10 +2,9 @@ from django.contrib.auth.decorators import login_required
 from django.utils.translation import ugettext as _
 from modoboa.lib.exceptions import ModoboaException
 from modoboa.lib.webutils import (
-    ajax_response, ajax_simple_response, _render_to_string
+    render_to_json_response, _render_to_string
 )
 from modoboa.extensions.admin.lib import needs_mailbox
-from modoboa.extensions.admin.exceptions import BadDestination
 from modoboa.extensions.admin.models import Alias, Mailbox
 from modoboa.extensions.admin.forms import ForwardForm
 
@@ -13,12 +12,7 @@ from modoboa.extensions.admin.forms import ForwardForm
 @login_required
 @needs_mailbox()
 def forward(request, tplname='admin/forward.html'):
-    try:
-        mb = request.user.mailbox_set.all()[0]
-    except IndexError:
-        raise ModoboaException(
-            _("You need a mailbox in order to define a forward")
-        )
+    mb = request.user.mailbox_set.all()[0]
     try:
         al = Alias.objects.get(address=mb.address,
                                domain__name=mb.domain.name)
@@ -28,28 +22,23 @@ def forward(request, tplname='admin/forward.html'):
         form = ForwardForm(request.POST)
         error = None
         if form.is_valid():
-            try:
-                if al is None:
-                    al = Alias()
-                    al.address = mb.address
-                    al.domain = mb.domain
-                    al.enabled = mb.user.is_active
-                intdests = []
-                if form.cleaned_data["keepcopies"]:
-                    intdests += [mb]
-                form.parse_dest()
-                al.save(int_rcpts=intdests, ext_rcpts=form.dests)
-                if request.user.group != "SimpleUsers":
-                    al.post_create(request.user)
-                return ajax_response(request, respmsg=_("Forward updated"))
-            except BadDestination, e:
-                error = str(e)
+            if al is None:
+                al = Alias()
+                al.address = mb.address
+                al.domain = mb.domain
+                al.enabled = mb.user.is_active
+            intdests = []
+            if form.cleaned_data["keepcopies"]:
+                intdests += [mb]
+            form.parse_dest()
+            al.save(int_rcpts=intdests, ext_rcpts=form.dests)
+            if request.user.group != "SimpleUsers":
+                al.post_create(request.user)
+            return render_to_json_response(_("Forward updated"))
 
-        return ajax_simple_response(dict(
-            status="ko",
-            errors=form.errors,
-            respmsg=error
-        ))
+        return render_to_json_response(
+            {'form_errors': form.errors}, status=400
+        )
 
     form = ForwardForm()
     if al is not None:
@@ -60,8 +49,7 @@ def forward(request, tplname='admin/forward.html'):
             pass
         else:
             form.fields["keepcopies"].initial = True
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": _render_to_string(request, tplname, {
             "form": form
         })
diff --git a/modoboa/extensions/limits/__init__.py b/modoboa/extensions/limits/__init__.py
index 5c991598f..7f49c549f 100644
--- a/modoboa/extensions/limits/__init__.py
+++ b/modoboa/extensions/limits/__init__.py
@@ -10,16 +10,22 @@ from django.contrib.contenttypes.models import ContentType
 from django.utils.translation import ugettext as _, ugettext_lazy
 from modoboa.lib import events, parameters
 from modoboa.core.extensions import ModoExtension, exts_pool
+from .models import LimitTemplates
 from .forms import ResourcePoolForm
 import controls
 
+levents = [
+    'GetExtraLimitTemplates'
+]
+
 
 class Limits(ModoExtension):
     name = "limits"
     label = "Limits"
     version = "1.0"
     description = ugettext_lazy(
-        "Per administrator resources to limit the number of objects they can create"
+        "Per administrator resources to limit the number of objects "
+        "they can create"
     )
 
     def init(self):
@@ -48,6 +54,7 @@ class Limits(ModoExtension):
     def load(self):
         from modoboa.extensions.limits.app_settings import ParametersForm
         parameters.register(ParametersForm, ugettext_lazy("Limits"))
+        events.declare(levents)
 
     def destroy(self):
         parameters.unregister()
@@ -74,7 +81,13 @@ def display_pool_usage(user, target, currentpage):
         if user.has_perm("admin.add_domain"):
             names += ["domain_admins_limit"]
     else:
-        names = ["domains_limit", "domain_aliases_limit"]
+        names = [
+            tpl[0] for tpl in LimitTemplates().templates
+            if tpl[0] not in ["domain_admins_limit", "mailboxes_limit",
+                              "mailbox_aliases_limit"]
+            and (len(tpl) == 3 or tpl[3] == user.group)
+        ]
+
     limits = user.limitspool.limit_set.filter(name__in=names, maxvalue__gt=0)
     if len(limits) == 0:
         return []
@@ -85,7 +98,8 @@ def display_pool_usage(user, target, currentpage):
 def extra_account_form(user, account=None):
     if not user.group in ["SuperAdmins", "Resellers"]:
         return []
-    if account is not None and not account.group in ["Resellers", "DomainAdmins"]:
+    if account is not None and \
+            not account.group in ["Resellers", "DomainAdmins"]:
         return []
 
     return [
@@ -126,7 +140,7 @@ def get_static_content(caller, user):
     margin: 5px 0;
 }
 
-.resource .progress { 
+.resource .progress {
     margin-bottom: 0px;
 }
 
diff --git a/modoboa/extensions/limits/app_settings.py b/modoboa/extensions/limits/app_settings.py
index 6ce6665cb..e5b510cff 100644
--- a/modoboa/extensions/limits/app_settings.py
+++ b/modoboa/extensions/limits/app_settings.py
@@ -39,3 +39,7 @@ class ParametersForm(AdminParametersForm):
         help_text=_("Maximum number of allowed aliases for a new administrator"),
         widget=forms.widgets.TextInput(attrs={"class": "span1"})
     )
+
+    def __init__(self, *args, **kwargs):
+        super(AdminParametersForm, self).__init__(*args, **kwargs)
+        self._load_extra_parameters('A')
diff --git a/modoboa/extensions/limits/controls.py b/modoboa/extensions/limits/controls.py
index 18a7b96c2..7ddd2f212 100644
--- a/modoboa/extensions/limits/controls.py
+++ b/modoboa/extensions/limits/controls.py
@@ -6,43 +6,27 @@
 """
 from modoboa.lib import events
 from modoboa.lib.permissions import get_object_owner
-from .lib import LimitReached
-from .models import limits_tpl, LimitsPool
+from .lib import LimitReached, inc_limit_usage, dec_limit_usage
+from .models import LimitTemplates, LimitsPool
 
 
-def check_limit(user, lname):
+def check_limit(user, lname, count=1):
     """Check if a user has reached a defined limit
 
     We check if the user will not reach the given limit after this
     creation.
 
-    Raise a ``LimitReached`` exception if the limit is reached.
-
     :param user: a ``User`` object
+    :param int count: the number of objects the user tries to create
+    :raises: ``LimitReached``
     """
     try:
-        if user.limitspool.will_be_reached(lname):
+        if user.limitspool.will_be_reached(lname, count):
             raise LimitReached(user.limitspool.get_limit(lname))
     except LimitsPool.DoesNotExist:
         pass
 
 
-def inc_limit(user, lname):
-    try:
-        user.limitspool.inc_curvalue(lname)
-    except LimitsPool.DoesNotExist:
-        pass
-
-
-def dec_limit(user, lname):
-    if user is None:
-        return
-    try:
-        user.limitspool.dec_curvalue(lname)
-    except LimitsPool.DoesNotExist:
-        pass
-
-
 def move_pool_resource(owner, user):
     """Move resource from one pool to another
 
@@ -54,7 +38,7 @@ def move_pool_resource(owner, user):
     except LimitsPool.DoesNotExist:
         return
     if not owner.is_superuser:
-        for ltpl in limits_tpl:
+        for ltpl in LimitTemplates().templates:
             l = user.limitspool.get_limit(ltpl[0])
             if l.maxvalue < 0:
                 continue
@@ -68,13 +52,13 @@ def move_pool_resource(owner, user):
 
 @events.observe('DomainCreated')
 def inc_nb_domains(user, domain):
-    inc_limit(user, 'domains_limit')
+    inc_limit_usage(user, 'domains_limit')
 
 
 @events.observe('DomainDeleted')
 def dec_nb_domains(domain):
     owner = get_object_owner(domain)
-    dec_limit(owner, 'domains_limit')
+    dec_limit_usage(owner, 'domains_limit')
     for domalias in domain.domainalias_set.all():
         dec_nb_domaliases(domalias)
     for mailbox in domain.mailbox_set.all():
@@ -85,7 +69,7 @@ def dec_nb_domains(domain):
 
 @events.observe('DomainAliasCreated')
 def inc_nb_domaliases(user, domalias):
-    inc_limit(user, 'domain_aliases_limit')
+    inc_limit_usage(user, 'domain_aliases_limit')
 
 
 @events.observe('DomainAliasDeleted')
@@ -96,12 +80,12 @@ def dec_nb_domaliases(domainaliases):
         domainaliases = [domainaliases]
     for domainalias in domainaliases:
         owner = get_object_owner(domainalias)
-        dec_limit(owner, 'domain_aliases_limit')
+        dec_limit_usage(owner, 'domain_aliases_limit')
 
 
 @events.observe('MailboxCreated')
 def inc_nb_mailboxes(user, mailbox):
-    inc_limit(user, 'mailboxes_limit')
+    inc_limit_usage(user, 'mailboxes_limit')
 
 
 @events.observe('MailboxDeleted')
@@ -112,23 +96,23 @@ def dec_nb_mailboxes(mailboxes):
         mailboxes = [mailboxes]
     for mailbox in mailboxes:
         owner = get_object_owner(mailbox)
-        dec_limit(owner, 'mailboxes_limit')
+        dec_limit_usage(owner, 'mailboxes_limit')
 
 
 @events.observe('MailboxAliasCreated')
 def inc_nb_mbaliases(user, mailboxalias):
-    inc_limit(user, 'mailbox_aliases_limit')
+    inc_limit_usage(user, 'mailbox_aliases_limit')
 
 
 @events.observe('MailboxAliasDeleted')
 def dec_nb_mbaliases(mailboxalias):
     owner = get_object_owner(mailboxalias)
-    dec_limit(owner, 'mailbox_aliases_limit')
+    dec_limit_usage(owner, 'mailbox_aliases_limit')
 
 
 @events.observe('CanCreate')
-def can_create_new_object(user, objtype):
-    check_limit(user, '%s_limit' % objtype)
+def can_create_new_object(user, objtype, count=1):
+    check_limit(user, '%s_limit' % objtype, count)
 
 
 @events.observe("AccountCreated")
@@ -140,12 +124,31 @@ def create_pool(user):
 
     if user.belongs_to_group("DomainAdmins"):
         check_limit(owner, 'domain_admins_limit')
-        inc_limit(owner, 'domain_admins_limit')
+        inc_limit_usage(owner, 'domain_admins_limit')
 
     if user.group in ["DomainAdmins", "Resellers"]:
-        p = LimitsPool(user=user)
-        p.save()
-        p.create_limits()
+        p, created = LimitsPool.objects.get_or_create(user=user)
+        p.create_limits(owner)
+
+
+@events.observe("UserCanSetRole")
+def user_can_set_role(user, role):
+    """Check if the user can still set this role.
+
+    The only interesting case concerns resellers defining new domain
+    administrators. We want to check if they are allowed to do this
+    operation before any modification is made to :keyword:`account`.
+
+    :param ``User`` user: connected user
+    :param str newrole: role to check
+    """
+    if role == 'DomainAdmins':
+        lname = 'domain_admins_limit'
+    else:
+        return [True]
+    if user.is_superuser or not user.limitspool.will_be_reached(lname):
+        return [True]
+    return [False]
 
 
 @events.observe("AccountModified")
@@ -164,19 +167,19 @@ def on_account_modified(old, new):
         except LimitsPool.DoesNotExist:
             p = LimitsPool(user=new)
             p.save()
-            p.create_limits()
+            p.create_limits(owner)
 
     if not new.group in ["DomainAdmins", "Resellers"]:
         move_pool_resource(owner, new)
 
     if old.oldgroup == "DomainAdmins":
         if new.group != "DomainAdmins":
-            dec_limit(owner, 'domain_admins_limit')
+            dec_limit_usage(owner, 'domain_admins_limit')
         return
 
     if new.group == "DomainAdmins":
         check_limit(owner, 'domain_admins_limit')
-        inc_limit(owner, 'domain_admins_limit')
+        inc_limit_usage(owner, 'domain_admins_limit')
 
 
 @events.observe("AccountDeleted")
@@ -188,4 +191,4 @@ def on_account_deleted(account, byuser, **kwargs):
     move_pool_resource(owner, account)
 
     if account.group == "DomainAdmins":
-        dec_limit(owner, 'domain_admins_limit')
+        dec_limit_usage(owner, 'domain_admins_limit')
diff --git a/modoboa/extensions/limits/forms.py b/modoboa/extensions/limits/forms.py
index 8a5ac4fcf..a763284e2 100644
--- a/modoboa/extensions/limits/forms.py
+++ b/modoboa/extensions/limits/forms.py
@@ -1,44 +1,26 @@
 # coding: utf-8
-
 from django import forms
 from django.utils.translation import ugettext as _, ugettext_lazy
 from modoboa.lib import parameters
-from .models import limits_tpl
+from .models import LimitTemplates
 from .lib import BadLimitValue, UnsufficientResource
 
 
 class ResourcePoolForm(forms.Form):
-    domain_admins_limit = forms.IntegerField(
-        label=ugettext_lazy("Domain admins"),
-        help_text=ugettext_lazy("Maximum number of domain administrators this user can create")
-    )
-    domains_limit = forms.IntegerField(
-        label=ugettext_lazy("Domains"),
-        help_text=ugettext_lazy("Maximum number of domains this user can create")
-    )
-    domain_aliases_limit = forms.IntegerField(
-        label=ugettext_lazy("Domain aliases"),
-        help_text=ugettext_lazy("Maximum number of domain aliases this user can create")
-    )
-    mailboxes_limit = forms.IntegerField(
-        label=ugettext_lazy("Mailboxes"),
-        help_text=ugettext_lazy("Maximum number of mailboxes this user can create")
-    )
-    mailbox_aliases_limit = forms.IntegerField(
-        label=ugettext_lazy("Mailbox aliases"),
-        help_text=ugettext_lazy("Maximum number of mailbox aliases this user can create")
-    )
 
     def __init__(self, *args, **kwargs):
+        self.account = None
         if "instance" in kwargs:
             self.account = kwargs["instance"]
             del kwargs["instance"]
         super(ResourcePoolForm, self).__init__(*args, **kwargs)
+        for tpl in LimitTemplates().templates:
+            if len(tpl) > 3 and self.account is not None and self.account.group != tpl[3]:
+                continue
+            self.fields[tpl[0]] = forms.IntegerField(
+                label=tpl[1], help_text=tpl[2]
+            )
         if hasattr(self, "account"):
-            if self.account.group != "Resellers":
-                del self.fields["domain_admins_limit"]
-                del self.fields["domains_limit"]
-                del self.fields["domain_aliases_limit"]
             self.load_from_user(self.account)
 
     def check_limit_value(self, lname):
@@ -46,29 +28,30 @@ class ResourcePoolForm(forms.Form):
             raise forms.ValidationError(_("Invalid limit"))
         return self.cleaned_data[lname]
 
-    def clean_domains_limit(self):
-        return self.check_limit_value("domains_limit")
-
-    def clean_domain_aliases_limit(self):
-        return self.check_limit_value("domain_aliases_limit")
-
-    def clean_mailboxes_limit(self):
-        return self.check_limit_value("mailboxes_limit")
-
-    def clean_mailbox_aliases_limit(self):
-        return self.check_limit_value("mailbox_aliases_limit")
+    def clean(self):
+        cleaned_data = super(ResourcePoolForm, self).clean()
+        for lname in self.fields.keys():
+            if not lname in self._errors and cleaned_data[lname] < -1:
+                self._errors[lname] = self.error_class([_('Invalid limit')])
+                del cleaned_data[lname]
+        return cleaned_data
 
     def load_from_user(self, user):
-        for l in limits_tpl:
-            if not l[0] in self.fields:
-                continue
-            self.fields[l[0]].initial = user.limitspool.getmaxvalue(l[0])
+        for lname in self.fields.keys():
+            self.fields[lname].initial = user.limitspool.getmaxvalue(lname)
             # The following lines will become useless in a near
             # future.
-            if self.fields[l[0]].initial == -2:
-                self.fields[l[0]].initial = parameters.get_admin("DEFLT_%s" % l[0].upper())
+            if self.fields[lname].initial == -2:
+                self.fields[lname].initial = parameters.get_admin("DEFLT_%s" % lname.upper())
 
     def allocate_from_pool(self, limit, pool):
+        """Allocate resource using an existing pool.
+
+        When a reseller creates a domain administrator, he generally
+        assigns him resource to create new objetcs. As a reseller may
+        also be limited, the resource he gives is taken from its own
+        pool.
+        """
         ol = pool.get_limit(limit.name)
         if ol.maxvalue == -2:
             raise BadLimitValue(_("Your resources are not initialized yet"))
@@ -92,7 +75,7 @@ class ResourcePoolForm(forms.Form):
         from modoboa.lib.permissions import get_object_owner
 
         owner = get_object_owner(self.account)
-        for ltpl in limits_tpl:
+        for ltpl in LimitTemplates().templates:
             if not ltpl[0] in self.cleaned_data:
                 continue
             l = self.account.limitspool.limit_set.get(name=ltpl[0])
diff --git a/modoboa/extensions/limits/lib.py b/modoboa/extensions/limits/lib.py
index 5a395b86c..a4f7b2f1d 100644
--- a/modoboa/extensions/limits/lib.py
+++ b/modoboa/extensions/limits/lib.py
@@ -6,9 +6,12 @@
 """
 from django.utils.translation import ugettext as _
 from modoboa.lib.exceptions import ModoboaException
+from .models import LimitsPool
 
 
 class LimitReached(ModoboaException):
+    http_code = 403
+
     def __init__(self, limit):
         self.limit = limit
 
@@ -17,6 +20,8 @@ class LimitReached(ModoboaException):
 
 
 class UnsufficientResource(ModoboaException):
+    http_code = 424
+
     def __init__(self, limit):
         self.limit = limit
 
@@ -26,3 +31,22 @@ class UnsufficientResource(ModoboaException):
 
 class BadLimitValue(ModoboaException):
     pass
+
+
+def inc_limit_usage(user, lname):
+    """Increase a given limit usage.
+
+    """
+    try:
+        user.limitspool.inc_curvalue(lname)
+    except LimitsPool.DoesNotExist:
+        pass
+
+
+def dec_limit_usage(user, lname):
+    if user is None:
+        return
+    try:
+        user.limitspool.dec_curvalue(lname)
+    except LimitsPool.DoesNotExist:
+        pass
diff --git a/modoboa/extensions/limits/models.py b/modoboa/extensions/limits/models.py
index 80f521289..c249aa27b 100644
--- a/modoboa/extensions/limits/models.py
+++ b/modoboa/extensions/limits/models.py
@@ -2,27 +2,53 @@
 from django.db import models
 from django.utils.translation import ugettext as _, ugettext_lazy
 from modoboa.lib import parameters
+from modoboa.lib.singleton import Singleton
 from django.conf import settings
+from modoboa.lib import events
 
-limits_tpl = [
-    ("domain_admins_limit", ugettext_lazy("Domain admins")),
-    ("domains_limit", ugettext_lazy("Domains")),
-    ("domain_aliases_limit", ugettext_lazy("Domain aliases")),
-    ("mailboxes_limit", ugettext_lazy("Mailboxes")),
-    ("mailbox_aliases_limit", ugettext_lazy("Mailbox aliases"))
-]
+
+class LimitTemplates(Singleton):
+
+    def __init__(self):
+        self.templates = [
+            ("domain_admins_limit", ugettext_lazy("Domain admins"),
+             ugettext_lazy("Maximum number of domain administrators this user can create"),
+             'Resellers'),
+            ("domains_limit", ugettext_lazy("Domains"),
+             ugettext_lazy("Maximum number of domains this user can create"),
+             'Resellers'),
+            ("domain_aliases_limit", ugettext_lazy("Domain aliases"),
+             ugettext_lazy("Maximum number of domain aliases this user can create"),
+             'Resellers'),
+            ("mailboxes_limit", ugettext_lazy("Mailboxes"),
+             ugettext_lazy("Maximum number of mailboxes this user can create")),
+            ("mailbox_aliases_limit", ugettext_lazy("Mailbox aliases"),
+             ugettext_lazy("Maximum number of mailbox aliases this user can create"))
+        ]
+        self.templates += events.raiseQueryEvent('GetExtraLimitTemplates')
 
 
 class LimitsPool(models.Model):
     user = models.OneToOneField(settings.AUTH_USER_MODEL)
 
-    def create_limits(self):
-        for ltpl in limits_tpl:
-            l = Limit()
-            l.name = ltpl[0]
-            l.pool = self
-            l.maxvalue = int(parameters.get_admin("DEFLT_%s" % ltpl[0].upper()))
-            l.save()
+    def create_limits(self, creator):
+        """Create limits for this pool.
+
+        All limits defined into ``LimitTemplates`` will be created. If
+        the creator is a super administrator, the default maximum values
+        will be used.
+
+        :param ``User`` creator: user creating this pool
+        """
+        for ltpl in LimitTemplates().templates:
+            try:
+                Limit.objects.get(name=ltpl[0], pool=self)
+            except Limit.DoesNotExist:
+                maxvalue = int(parameters.get_admin("DEFLT_%s" % ltpl[0].upper())) \
+                    if creator.is_superuser else 0
+                Limit.objects.create(
+                    name=ltpl[0], pool=self, maxvalue=maxvalue
+                )
 
     def getcurvalue(self, lname):
         l = self.limit_set.get(name=lname)
@@ -32,6 +58,11 @@ class LimitsPool(models.Model):
         l = self.limit_set.get(name=lname)
         return l.maxvalue
 
+    def set_maxvalue(self, lname, value):
+        l = self.limit_set.get(name=lname)
+        l.maxvalue = value
+        l.save()
+
     def inc_curvalue(self, lname, nb=1):
         l = self.limit_set.get(name=lname)
         l.curvalue += nb
@@ -92,7 +123,7 @@ class Limit(models.Model):
 
     @property
     def label(self):
-        for l in limits_tpl:
+        for l in LimitTemplates().templates:
             if l[0] == self.name:
                 return l[1]
         return ""
diff --git a/modoboa/extensions/limits/tests.py b/modoboa/extensions/limits/tests.py
index 410b9f30c..0bae19785 100644
--- a/modoboa/extensions/limits/tests.py
+++ b/modoboa/extensions/limits/tests.py
@@ -1,8 +1,13 @@
 from django.core.urlresolvers import reverse
 from modoboa.lib.tests import ExtTestCase
-from modoboa.core.factories import UserFactory
-from modoboa.extensions.admin.factories import DomainFactory, MailboxFactory
+from modoboa.lib import parameters
 from modoboa.core.models import User
+from modoboa.core.factories import UserFactory
+from modoboa.extensions.admin.factories import (
+    DomainFactory, MailboxFactory, populate_database
+)
+from modoboa.extensions.admin.models import Alias, Domain, DomainAlias
+from modoboa.extensions.limits.models import LimitTemplates
 
 
 class PermissionsTestCase(ExtTestCase):
@@ -26,13 +31,342 @@ class PermissionsTestCase(ExtTestCase):
         values = dict(
             username="reseller@test.com", first_name="Reseller", last_name="",
             password1="toto", password2="toto", role="Resellers",
-            is_active=True, email="reseller@test.com", stepid=2
+            is_active=True, email="reseller@test.com", stepid='step2'
         )
-        self.check_ajax_post(reverse("modoboa.extensions.admin.views.identity.newaccount"), values)
+        self.ajax_post(reverse("modoboa.extensions.admin.views.identity.newaccount"), values)
         account = User.objects.get(username="reseller@test.com")
         self.clt.logout()
         self.clt.login(username="admin@test.com", password="toto")
-        self.check_ajax_get(
+        resp = self.ajax_post(
             reverse("modoboa.extensions.admin.views.identity.delaccount", args=[account.id]),
-            {}, status="ko", respmsg="Permission denied"
+            {}, status=403
         )
+        self.assertEqual(resp, "Permission denied")
+
+
+class ResourceTestCase(ExtTestCase):
+    fixtures = ["initial_users.json"]
+    name = "limits"
+
+    def setUp(self):
+        super(ResourceTestCase, self).setUp()
+        populate_database()
+        for tpl in LimitTemplates().templates:
+            parameters.save_admin('DEFLT_%s' % tpl[0].upper(), 2, app='limits')
+
+    def _create_account(self, username, role='SimpleUsers', status=200):
+        values = dict(
+            username=username, first_name="Tester", last_name="Toto",
+            password1="toto", password2="toto", role=role,
+            quota_act=True,
+            is_active=True, email=username, stepid='step2',
+        )
+        return self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.newaccount"),
+            values, status
+        )
+
+    def _create_alias(self, email, rcpt='user@test.com', status=200):
+        values = dict(
+            email=email, recipients=rcpt, enabled=True
+        )
+        return self.ajax_post(
+            reverse("modoboa.extensions.admin.views.alias.newalias"),
+            values, status
+        )
+
+    def _create_domain(self, name, status=200, withtpl=False):
+        values = {
+            "name": name, "quota": 100, "create_dom_admin": "no",
+            "create_aliases": "no", "stepid": 'step2'
+        }
+        if withtpl:
+            values['create_dom_admin'] = 'yes'
+            values['dom_admin_username'] = 'admin'
+            values['create_aliases'] = 'yes'
+        return self.ajax_post(
+            reverse("modoboa.extensions.admin.views.domain.newdomain"),
+            values, status
+        )
+
+    def _domain_alias_operation(self, optype, domain, name, status=200):
+        dom = Domain.objects.get(name=domain)
+        values = {
+            'name': dom.name, 'quota': dom.quota, 'enabled': dom.enabled,
+        }
+        aliases = [alias.name for alias in dom.domainalias_set.all()]
+        if optype == 'add':
+            aliases.append(name)
+        else:
+            aliases.remove(name)
+        for cpt, alias in enumerate(aliases):
+            fname = 'aliases' if not cpt else 'aliases_%d' % cpt
+            values[fname] = alias
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.domain.editdomain",
+                    args=[dom.id]),
+            values, status
+        )
+
+    def _check_limit(self, name, curvalue, maxvalue):
+        l = self.user.limitspool.get_limit('%s_limit' % name)
+        self.assertEqual(l.curvalue, curvalue)
+        self.assertEqual(l.maxvalue, maxvalue)
+
+
+class DomainAdminTestCase(ResourceTestCase):
+
+    def setUp(self):
+        super(DomainAdminTestCase, self).setUp()
+        self.user = User.objects.get(username='admin@test.com')
+        self.user.limitspool.set_maxvalue('mailboxes_limit', 2)
+        self.user.limitspool.set_maxvalue('mailbox_aliases_limit', 2)
+        self.clt.logout()
+        self.clt.login(username='admin@test.com', password='toto')
+
+    def test_mailboxes_limit(self):        
+        self._create_account('tester1@test.com')
+        self._check_limit('mailboxes', 1, 2)
+        self._create_account('tester2@test.com')
+        self._check_limit('mailboxes', 2, 2)
+        resp = self._create_account('tester3@test.com', status=403)
+        self._check_limit('mailboxes', 2, 2)
+        self.ajax_post(
+            reverse('modoboa.extensions.admin.views.identity.delaccount',
+                    args=[User.objects.get(username='tester2@test.com').id]),
+            {}
+        )
+        self._check_limit('mailboxes', 1, 2)
+
+    def test_aliases_limit(self):
+        self._create_alias('alias1@test.com')
+        self._check_limit('mailbox_aliases', 1, 2)
+        self._create_alias('alias2@test.com')
+        self._check_limit('mailbox_aliases', 2, 2)
+        resp = self._create_alias('alias3@test.com', status=403)
+        self._check_limit('mailbox_aliases', 2, 2)
+        self.ajax_post(
+            reverse('modoboa.extensions.admin.views.alias.delalias') + '?selection=%d' \
+                % Alias.objects.get(address='alias2', domain__name='test.com').id,
+            {}
+        )
+        self._check_limit('mailbox_aliases', 1, 2)
+
+    def test_aliases_limit_through_account_form(self):
+        user = User.objects.get(username='user@test.com')
+        values = dict(
+            username=user.username, role=user.group,
+            is_active=user.is_active, email=user.email, quota_act=True,
+            aliases="alias1@test.com", aliases_1="alias2@test.com"
+        )
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values
+        )
+        Alias.objects.get(address='alias1', domain__name='test.com')
+        self._check_limit('mailbox_aliases', 2, 2)
+
+
+class ResellerTestCase(ResourceTestCase):
+
+    def setUp(self):
+        super(ResellerTestCase, self).setUp()
+        self.user = UserFactory.create(
+            username='reseller', groups=('Resellers',)
+        )
+        self.clt.logout()
+        self.clt.login(username='reseller', password='toto')
+
+    def test_domains_limit(self):
+        self._create_domain('domain1.tld')
+        self._check_limit('domains', 1, 2)
+        self._create_domain('domain2.tld')
+        self._check_limit('domains', 2, 2)
+        resp = self._create_domain('domain3.tld', 403)
+        self._check_limit('domains', 2, 2)
+        self.ajax_post(
+            reverse('modoboa.extensions.admin.views.domain.deldomain',
+                    args=[Domain.objects.get(name='domain2.tld').id]),
+            {}
+        )
+        self._check_limit('domains', 1, 2)
+
+    def test_domain_aliases_limit(self):
+        self._create_domain('pouet.com')
+        self._domain_alias_operation('add', 'pouet.com', 'domain_alias1.tld')
+        self._check_limit('domain_aliases', 1, 2)
+        self._domain_alias_operation('add', 'pouet.com', 'domain_alias2.tld')
+        self._check_limit('domain_aliases', 2, 2)
+        resp = self._domain_alias_operation(
+            'add', 'pouet.com', 'domain_alias3.tld', 403
+        )
+        self._check_limit('domain_aliases', 2, 2)
+        self._domain_alias_operation('delete', 'pouet.com', 'domain_alias2.tld')
+        self._check_limit('domain_aliases', 1, 2)
+
+    def test_domain_admins_limit(self):
+        self._create_domain('domain.tld')
+        self._create_account('admin1@domain.tld', role='DomainAdmins')
+        self._check_limit('domain_admins', 1, 2)
+        self._create_account('admin2@domain.tld', role='DomainAdmins')
+        self._check_limit('domain_admins', 2, 2)
+        resp = self._create_account('admin3@domain.tld', role='DomainAdmins', status=400)
+        self.assertEqual(
+            resp['form_errors']['role'][0],
+            'Select a valid choice. DomainAdmins is not one of the available choices.'
+        )
+        self._check_limit('domain_admins', 2, 2)
+        
+        self.user.limitspool.set_maxvalue('mailboxes_limit', 3)
+        self._create_account('user1@domain.tld')
+        user = User.objects.get(username='user1@domain.tld')
+        values = {
+            'username': user.username, 'role': 'DomainAdmins', 'quota_act': True,
+            'is_active': user.is_active, 'email': user.email
+        }
+        resp = self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values, status=400
+        )
+        self.assertEqual(
+            resp['form_errors']['role'][0],
+            'Select a valid choice. DomainAdmins is not one of the available choices.'
+        )
+        self._check_limit('domain_admins', 2, 2)
+
+    def test_domain_admin_resource_are_empty(self):
+        self._create_domain('domain.tld')
+        self._create_account('admin1@domain.tld', role='DomainAdmins')
+        domadmin = User.objects.get(username='admin1@domain.tld')
+        for l in ['mailboxes', 'mailbox_aliases']:
+            self.assertEqual(
+                domadmin.limitspool.get_limit('%s_limit' % l).maxvalue, 0
+            )
+
+    def test_domain_admins_limit_from_domain_tpl(self):
+        self.user.limitspool.set_maxvalue('domains_limit', 3)
+        self._create_domain('domain1.tld', withtpl=True)
+        self._create_domain('domain2.tld', withtpl=True)
+        self._check_limit('domain_admins', 2, 2)
+        self._check_limit('domains', 2, 3)
+        resp = self._create_domain('domain3.tld', status=200, withtpl=True)
+        self._check_limit('domain_admins', 2, 2)
+        self._check_limit('domains', 3, 3)
+
+    def test_allocate_from_pool(self):
+        self._create_domain('domain.tld')
+        self._create_account('admin1@domain.tld', role='DomainAdmins')
+        user = User.objects.get(username='admin1@domain.tld')
+
+        # Give 1 mailbox and 2 aliases to the admin -> should work
+        values = {
+            'username': user.username, 'role': user.group, 'quota_act': True,
+            'is_active': user.is_active, 'email': user.email,
+            'mailboxes_limit': 1, 'mailbox_aliases_limit': 2
+        }
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values
+        )
+        self._check_limit('mailboxes', 1, 1)
+        self._check_limit('mailbox_aliases', 0, 0)
+
+        # Delete the admin -> resources should go back to the
+        # reseller's pool
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.delaccount",
+                    args=[user.id]),
+            {}
+        )
+        self._check_limit('mailboxes', 0, 2)
+        self._check_limit('mailbox_aliases', 0, 2)
+
+    def test_restore_resources(self):
+        self._create_domain('domain.tld')
+        dom = Domain.objects.get(name='domain.tld')
+        self._create_account('admin1@domain.tld', role='DomainAdmins')
+        user = User.objects.get(username='admin1@domain.tld')
+        values = {
+            'username': user.username, 'role': user.group, 'quota_act': True,
+            'is_active': user.is_active, 'email': user.email,
+            'mailboxes_limit': 1, 'mailbox_aliases_limit': 2
+        }
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values
+        )
+        dom.add_admin(user)
+        self.clt.logout()
+        self.clt.login(username='admin1@domain.tld', password='toto')
+        self._create_account('user1@domain.tld')
+        self._create_alias('alias1@domain.tld', 'user1@domain.tld')
+        self._create_alias('alias2@domain.tld', 'user1@domain.tld')
+        self.clt.logout()
+        self.clt.login(username='reseller', password='toto')
+        # Delete the admin -> resources should go back to the
+        # reseller's pool
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.delaccount",
+                    args=[user.id]),
+            {}
+        )
+        self._check_limit('mailboxes', 1, 2)
+        self._check_limit('mailbox_aliases', 2, 2)
+
+    def test_change_role(self):
+        self._create_domain('domain.tld')
+        self._create_account('admin1@domain.tld', role='DomainAdmins')
+        user = User.objects.get(username='admin1@domain.tld')
+
+        # Give 1 mailbox and 2 aliases to the admin -> should work
+        values = {
+            'username': user.username, 'role': user.group, 'quota_act': True,
+            'is_active': user.is_active, 'email': user.email,
+            'mailboxes_limit': 1, 'mailbox_aliases_limit': 2
+        }
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values
+        )
+        self._check_limit('mailboxes', 1, 1)
+        self._check_limit('mailbox_aliases', 0, 0)
+
+        # Change admin role to SimpleUser -> resources should go back
+        # to the reseller.
+        values = {
+            'username': user.username, 'role': 'SimpleUsers', 'quota_act': True,
+            'is_active': user.is_active, 'email': user.email,
+        }
+        self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values
+        )
+        self._check_limit('mailboxes', 1, 2)
+        self._check_limit('mailbox_aliases', 0, 2)
+        
+
+    def test_allocate_too_much(self):
+        self._create_domain('domain.tld')
+        self._create_account('admin1@domain.tld', role='DomainAdmins')
+        user = User.objects.get(username='admin1@domain.tld')
+
+        # Give 2 mailboxes and 3 aliases to the admin -> should fail.
+        values = {
+            'username': user.username, 'role': user.group, 'quota_act': True,
+            'is_active': user.is_active, 'email': user.email,
+            'mailboxes_limit': 2, 'mailbox_aliases_limit': 3
+        }
+        resp = self.ajax_post(
+            reverse("modoboa.extensions.admin.views.identity.editaccount",
+                    args=[user.id]),
+            values, 424
+        )
+        self.assertEqual(resp, 'Not enough resources')
+        self._check_limit('mailboxes', 1, 2)
+        self._check_limit('mailbox_aliases', 0, 2)
diff --git a/modoboa/extensions/postfix_autoreply/views.py b/modoboa/extensions/postfix_autoreply/views.py
index 2766d533e..7b234966b 100644
--- a/modoboa/extensions/postfix_autoreply/views.py
+++ b/modoboa/extensions/postfix_autoreply/views.py
@@ -3,7 +3,7 @@ from datetime import date
 from django.contrib.auth.decorators import login_required
 from django.utils.translation import ugettext as _
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string
+    render_to_json_response, _render_to_string
 )
 from modoboa.extensions.admin.lib import needs_mailbox
 from modoboa.extensions.admin.models import Mailbox
@@ -29,24 +29,20 @@ def autoreply(request, tplname="postfix_autoreply/autoreply.html"):
             arm.untildate = form.cleaned_data["untildate"]
             arm.mbox = mb
             arm.save()
-            return ajax_simple_response(dict(
-                status="ok",
-                respmsg=_("Auto reply message updated successfully.")
-            ))
+            return render_to_json_response(
+                _("Auto reply message updated successfully.")
+            )
 
-        return ajax_simple_response({
-            "status": "ko",
-            "errors": form.errors,
-            "onload_cb": "autoreply_cb"
-        })
+        return render_to_json_response(
+            {"form_errors": form.errors}, status=400
+        )
 
     form = ARmessageForm(instance=arm)
     if arm is not None:
         form.fields['untildate'].initial = arm.untildate
     else:
         form.fields['untildate'].initial = date.today()
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "content": _render_to_string(request, tplname, {"form": form}),
         "onload_cb": "autoreply_cb"
     })
diff --git a/modoboa/extensions/postfix_relay_domains/__init__.py b/modoboa/extensions/postfix_relay_domains/__init__.py
index 912da41f4..151462236 100644
--- a/modoboa/extensions/postfix_relay_domains/__init__.py
+++ b/modoboa/extensions/postfix_relay_domains/__init__.py
@@ -1,5 +1,7 @@
 # coding: utf-8
 from django.core.urlresolvers import reverse
+from django.contrib.auth.models import Group, Permission
+from django.contrib.contenttypes.models import ContentType
 from django.template import Template, Context
 from django.conf import settings
 from django.utils.translation import ugettext_lazy
@@ -10,6 +12,9 @@ from .models import RelayDomain, RelayDomainAlias, Service
 
 extension_events = [
     "RelayDomainCreated",
+    "RelayDomainDeleted",
+    "RelayDomainAliasCreated",
+    "RelayDomainAliasDeleted"
 ]
 
 
@@ -27,15 +32,41 @@ class PostfixRelayDomains(ModoExtension):
         """
         for service_name in ['relay', 'smtp']:
             Service.objects.get_or_create(name=service_name)
+        if not exts_pool.is_extension_enabled('limits'):
+            return
+
+        from modoboa.core.models import User
+        from modoboa.extensions.limits import controls
+
+        for u in User.objects.all():
+            controls.create_pool(u)
+
+        grp = Group.objects.get(name='Resellers')
+        for model in [RelayDomain, RelayDomainAlias, Service]:
+            ct = ContentType.objects.get_for_model(model)
+            name = model.__name__.lower()
+            for action in ['add', 'change', 'delete']:
+                grp.permissions.add(
+                    Permission.objects.get(
+                        content_type=ct, codename='%s_%s' % (action, name)
+                    )
+                )
+        grp.save()
 
     def load(self):
         from .app_settings import AdminParametersForm
 
-        parameters.register(AdminParametersForm, ugettext_lazy("Relay domains"))
+        parameters.register(
+            AdminParametersForm, ugettext_lazy("Relay domains")
+        )
         events.declare(extension_events)
+        if not exts_pool.is_extension_enabled('limits'):
+            return
+        import limits_controls
 
     def destroy(self):
         events.unregister('GetExtraDomainEntries', extra_domain_entries)
+        events.unregister('GetExtraParameters', extra_parameters)
 
 exts_pool.register_extension(PostfixRelayDomains)
 
@@ -132,3 +163,41 @@ def check_domain_name():
         (RelayDomain, ugettext_lazy('relay domain')),
         (RelayDomainAlias, ugettext_lazy('relay domain alias'))
     ]
+
+
+@events.observe('GetExtraLimitTemplates')
+def extra_limit_templates():
+    return [
+        ('relay_domains_limit', ugettext_lazy('Relay domains'),
+         ugettext_lazy('Maximum number of relay domains this user can create'),
+         'Resellers'),
+        ("relay_domain_aliases_limit", ugettext_lazy("Relay domain aliases"),
+         ugettext_lazy('Maximum number of relay domain aliases this user can create'),
+         'Resellers'),
+    ]
+
+
+@events.observe('GetExtraParameters')
+def extra_parameters(app, level):
+    from django import forms
+
+    if app != 'limits' or level != 'A':
+        return {}
+    return {
+        'deflt_relay_domains_limit': forms.IntegerField(
+            label=ugettext_lazy("Relay domains"),
+            initial=0,
+            help_text=ugettext_lazy(
+                "Maximum number of allowed relay domains for a new administrator"
+            ),
+            widget=forms.widgets.TextInput(attrs={"class": "span1"})
+        ),
+        'deflt_relay_domain_aliases_limit': forms.IntegerField(
+            label=ugettext_lazy("Relay domain aliases"),
+            initial=0,
+            help_text=ugettext_lazy(
+                "Maximum number of allowed relay domain aliases for a new administrator"
+            ),
+            widget=forms.widgets.TextInput(attrs={"class": "span1"})
+        )
+    }
diff --git a/modoboa/extensions/postfix_relay_domains/app_settings.py b/modoboa/extensions/postfix_relay_domains/app_settings.py
index d84de1aec..49d17ae0c 100644
--- a/modoboa/extensions/postfix_relay_domains/app_settings.py
+++ b/modoboa/extensions/postfix_relay_domains/app_settings.py
@@ -1,6 +1,5 @@
 from django import forms
 from django.utils.translation import ugettext_lazy
-from modoboa.lib.formutils import SeparatorField
 from modoboa.lib import parameters
 
 
diff --git a/modoboa/extensions/postfix_relay_domains/forms.py b/modoboa/extensions/postfix_relay_domains/forms.py
index f3100bd68..767caeb3a 100644
--- a/modoboa/extensions/postfix_relay_domains/forms.py
+++ b/modoboa/extensions/postfix_relay_domains/forms.py
@@ -1,6 +1,7 @@
 from django import forms
 from django.http import QueryDict
 from django.utils.translation import ugettext as _, ugettext_lazy
+from modoboa.lib import events
 from modoboa.lib.formutils import DynamicForm, DomainNameField
 from modoboa.extensions.admin.models import Domain, DomainAlias
 from .models import RelayDomain, RelayDomainAlias
@@ -92,23 +93,31 @@ class RelayDomainForm(forms.ModelForm, DynamicForm):
         rd = super(RelayDomainForm, self).save(commit=False)
         if commit:
             rd.save()
+            aliases = []
             for k, v in self.cleaned_data.iteritems():
                 if not k.startswith("aliases"):
                     continue
                 if v in ["", None]:
                     continue
-                try:
-                    rd.relaydomainalias_set.get(name=v)
-                except RelayDomainAlias.DoesNotExist:
-                    pass
-                else:
-                    continue
-                #events.raiseEvent("CanCreate", user, "domain_aliases")
-                al = RelayDomainAlias(name=v, target=rd, enabled=rd.enabled)
-                al.save(creator=user)
-
+                aliases.append(v)
             for rdalias in rd.relaydomainalias_set.all():
-                if not filter(lambda name: self.cleaned_data[name] == rdalias.name,
-                              self.cleaned_data.keys()):
+                if not rdalias.name in aliases:
                     rdalias.delete()
+                else:
+                    aliases.remove(rdalias.name)
+            if aliases:
+                events.raiseEvent(
+                    "CanCreate", user, "relay_domain_aliases", len(aliases)
+                )
+                for alias in aliases:
+                    try:
+                        rd.relaydomainalias_set.get(name=alias)
+                    except RelayDomainAlias.DoesNotExist:
+                        pass
+                    else:
+                        continue
+                    al = RelayDomainAlias(
+                        name=alias, target=rd, enabled=rd.enabled
+                    )
+                    al.save(creator=user)
         return rd
diff --git a/modoboa/extensions/postfix_relay_domains/limits_controls.py b/modoboa/extensions/postfix_relay_domains/limits_controls.py
new file mode 100644
index 000000000..9966945e7
--- /dev/null
+++ b/modoboa/extensions/postfix_relay_domains/limits_controls.py
@@ -0,0 +1,31 @@
+from modoboa.lib import events
+from modoboa.lib.permissions import get_object_owner
+from modoboa.extensions.limits.lib import inc_limit_usage, dec_limit_usage
+from .models import RelayDomainAlias
+
+
+@events.observe('RelayDomainCreated')
+def inc_relaydomains_count(user, rdomain):
+    inc_limit_usage(user, 'relay_domains_limit')
+
+
+@events.observe('RelayDomainDeleted')
+def dec_relaydomains_count(rdomain):
+    owner = get_object_owner(rdomain)
+    dec_limit_usage(owner, 'relay_domains_limit')
+    for rdomalias in rdomain.relaydomainalias_set.all():
+        dec_rdomaliases_count(rdomalias)
+
+
+@events.observe('RelayDomainAliasCreated')
+def inc_rdomaliases_count(user, rdomalias):
+    inc_limit_usage(user, 'relay_domain_aliases_limit')
+
+
+@events.observe('RelayDomainAliasDeleted')
+def dec_rdomaliases_count(rdomainaliases):
+    if isinstance(rdomainaliases, RelayDomainAlias):
+        rdomainaliases = [rdomainaliases]
+    for rdomainalias in rdomainaliases:
+        owner = get_object_owner(rdomainalias)
+        dec_limit_usage(owner, 'relay_domain_aliases_limit')
diff --git a/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js b/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js
index 830e3e977..f14188ee0 100644
--- a/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js
+++ b/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js
@@ -16,6 +16,15 @@ RelayDomains.prototype = {
     initialize: function(options) {
         this.options = $.extend({}, this.defaults, options);
         admin.register_tag_handler("srv", this.srv_tag_handler);
+        $(document).bind('domain_listing_refresh', this.listing_refresh_cb);
+    },
+
+    listing_refresh_cb: function() {
+        $("a[name=delrelaydomain]").confirm({
+            question: function() { return this.$element.attr('title'); },
+            method: "DELETE",
+            success_cb: $.proxy(admin.reload_listing, admin)
+        });
     },
 
     launch_scan: function(e) {
@@ -54,7 +63,7 @@ RelayDomains.prototype = {
         $('input:text:visible:first').focus();
         $("#id_aliases").dynamic_input();
         $(".submit").on('click', $.proxy(function(e) {
-            simple_ajax_form_post2(e, {
+            simple_ajax_form_post(e, {
                 formid: "rdomform",
                 reload_on_success: false,
                 success_cb: $.proxy(admin.reload_listing, admin)
diff --git a/modoboa/extensions/postfix_relay_domains/tests.py b/modoboa/extensions/postfix_relay_domains/tests.py
index 501deb776..dab97161c 100644
--- a/modoboa/extensions/postfix_relay_domains/tests.py
+++ b/modoboa/extensions/postfix_relay_domains/tests.py
@@ -1,16 +1,13 @@
-"""
-This file demonstrates writing tests using the unittest module. These will pass
-when you run "manage.py test".
-
-Replace this with more appropriate tests for your application.
-"""
-
-from django.test import TestCase
+from modoboa.lib.tests import ExtTestCase
+from modoboa.extensions.admin import factories
 
 
-class SimpleTest(TestCase):
-    def test_basic_addition(self):
-        """
-        Tests that 1 + 1 always equals 2.
-        """
-        self.assertEqual(1 + 1, 2)
+class RelayDomainsTestCase(ExtTestCase):
+    fixtures = ["initial_users.json"]
+    name = "postfix_relay_domains"
+
+    def setUp(self):
+        super(RelayDomainsTestCase, self).setUp()
+        factories.populate_database()
+
+    
diff --git a/modoboa/extensions/postfix_relay_domains/views.py b/modoboa/extensions/postfix_relay_domains/views.py
index 0a4281d0d..5eded6ca3 100644
--- a/modoboa/extensions/postfix_relay_domains/views.py
+++ b/modoboa/extensions/postfix_relay_domains/views.py
@@ -4,24 +4,20 @@ from django.core.urlresolvers import reverse
 from django.utils.translation import ugettext as _
 from django.views.decorators.http import require_http_methods
 from django.contrib.auth.decorators import (
-    login_required, permission_required, user_passes_test
+    login_required, permission_required
 )
 from modoboa.lib import events
-from modoboa.lib.exceptions import ModoboaException, PermDeniedException
+from modoboa.lib.exceptions import PermDeniedException
 from modoboa.lib.webutils import render_to_json_response
 from .models import RelayDomain, Service
 from .forms import RelayDomainForm
 
 
 @login_required
-@permission_required("admin.add_relaydomain")
+@permission_required("postfix_relay_domains.add_relaydomain")
 @transaction.commit_on_success
 def create(request, tplname="postfix_relay_domains/relaydomain_form.html"):
-    commonctx = {"title": _("New relay domain"),
-                 "action_label": _("Create"),
-                 "action_classes": "submit",
-                 "action": reverse(create),
-                 "formid": "rdomform"}
+    events.raiseEvent("CanCreate", request.user, "relay_domains")
     if request.method == 'POST':
         form = RelayDomainForm(request.POST)
         if form.is_valid():
@@ -30,13 +26,21 @@ def create(request, tplname="postfix_relay_domains/relaydomain_form.html"):
             return render_to_json_response(
                 {"respmsg": _("Relay domain created")}
             )
-        return render_to_json_response(form.errors, status=400)
-    commonctx['form'] = RelayDomainForm()
-    return render(request, tplname, commonctx)
+        return render_to_json_response(
+            {'form_errors': form.errors}, status=400
+        )
+
+    ctx = {"title": _("New relay domain"),
+           "action_label": _("Create"),
+           "action_classes": "submit",
+           "action": reverse(create),
+           "formid": "rdomform",
+           "form": RelayDomainForm()}
+    return render(request, tplname, ctx)
 
 
 @login_required
-@permission_required("admin.change_relaydomain")
+@permission_required("postfix_relay_domains.change_relaydomain")
 def edit(request, rdom_id, tplname='postfix_relay_domains/relaydomain_form.html'):
     rdom = RelayDomain.objects.get(pk=rdom_id)
     if not request.user.can_access(rdom):
@@ -46,10 +50,11 @@ def edit(request, rdom_id, tplname='postfix_relay_domains/relaydomain_form.html'
         if form.is_valid():
             form.save(request.user)
             events.raiseEvent('RelayDomainModified', rdom)
-            return render_to_json_response(
-                {'respmsg': _('Relay domain modified')}
-            )
-        return render_to_json_response(form.errors, status=400)
+            return render_to_json_response(_('Relay domain modified'))
+
+        return render_to_json_response(
+            {'form_errors': form.errors}, status=400
+        )
     ctx = {
         'action': reverse(edit, args=[rdom.id]),
         'formid': 'rdomform',
@@ -62,19 +67,17 @@ def edit(request, rdom_id, tplname='postfix_relay_domains/relaydomain_form.html'
 
 
 @login_required
-@permission_required("admin.delete_relaydomain")
+@permission_required("postfix_relay_domains.delete_relaydomain")
 def delete(request, rdom_id):
     rdom = RelayDomain.objects.get(pk=rdom_id)
     if not request.user.can_access(rdom):
         raise PermDeniedException
     rdom.delete()
-    return render_to_json_response({
-        'status': 'ok', 'respmsg': _('Relay domain deleted')
-    })
+    return render_to_json_response(_('Relay domain deleted'))
 
 
 @login_required
-@user_passes_test(lambda u: u.is_superuser)
+@permission_required("postfix_relay_domains.add_service")
 @require_http_methods(["POST"])
 def scan_for_services(request):
     try:
diff --git a/modoboa/extensions/sievefilters/lib.py b/modoboa/extensions/sievefilters/lib.py
index 3cd57d338..6d6b7e1ae 100644
--- a/modoboa/extensions/sievefilters/lib.py
+++ b/modoboa/extensions/sievefilters/lib.py
@@ -5,11 +5,12 @@ from sievelib.managesieve import Client, Error
 from sievelib.parser import Parser
 from sievelib.factory import FiltersSet
 from modoboa.lib import parameters
+from modoboa.lib.exceptions import ModoboaException
 from modoboa.lib.connections import ConnectionsManager, ConnectionError
 
 
-class SieveClientError(Exception):
-    pass
+class SieveClientError(ModoboaException):
+    http_code = 424
 
 
 class SieveClient(object):
diff --git a/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js b/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js
index 7854c0c13..3c8336806 100644
--- a/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js
+++ b/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js
@@ -18,15 +18,13 @@ function removefilter(evt) {
 
     $.ajax({
         url: $this.attr("href"),
-        dataType: 'json',
-        success: function(response) {
-            if (response.status == "ok") {
-                history.update(true);
-                $("body").notify('success', response.respmsg, 2000);
-            } else {
-                $("body").notify('error', response.respmsg);
-            }
-        }
+        dataType: 'json'
+    }).done(function(response) {
+        history.update(true);
+        $("body").notify('success', response, 2000);
+    }).fail(function(jqxhr) {
+        var response = $.parseJSON(jqxhr.responseText);
+        $("body").notify('error', response);
     });
 }
 
@@ -181,16 +179,14 @@ function toggle_filter_state(event) {
     event.preventDefault();
     $.ajax({
         url: $this.attr("href"),
-        dataType: 'json',
-        success: function(response) {
-            if (response.status == "ok") {
-                $this.html(response.label);
-                $this.attr("class", "");
-                $this.addClass(response.color);
-            } else {
-                $("body").notify('error', response.respmsg);
-            }
-        }
+        dataType: 'json'
+    }).done(function(response) {
+        $this.html(response.label);
+        $this.attr("class", "");
+        $this.addClass(response.color);
+    }).fail(function(jqhxr) {
+        var response = $.parseJSON(jqxhr.responseText);
+        $("body").notify('error', response);
     });
 }
 
@@ -200,11 +196,13 @@ function move_filter(event) {
     event.preventDefault();
     $.ajax({
         url: $this.attr('href'),
-        dataType: 'json',
-        success: function(response) {
-            $("#set_content").html(response.content);
-            init_filters_list();
-        }
+        dataType: 'json'
+    }).done(function(response) {
+        $("#set_content").html(response.content);
+        init_filters_list();
+    }).fail(function(jqxhr) {
+        var response = $.parseJSON(jqxhr.responseText);
+        $("body").notify('error', response);
     });
 }
 
@@ -234,11 +232,10 @@ function filtersetform_cb() {
     $("#newfiltersset").find("input").keypress(function(e) {
         if (e.which == 13) e.preventDefault();
     });
-    $(".submit").one('click', function(e) {
+    $(".submit").on('click', function(e) {
         simple_ajax_form_post(e, {
             formid: "newfiltersset",
             reload_on_success: false,
-            error_cb: filtersetform_cb,
             success_cb: filterset_created
         });
     });
diff --git a/modoboa/extensions/sievefilters/templates/sievefilters/index.html b/modoboa/extensions/sievefilters/templates/sievefilters/index.html
index 2430cafdc..817d6fd51 100644
--- a/modoboa/extensions/sievefilters/templates/sievefilters/index.html
+++ b/modoboa/extensions/sievefilters/templates/sievefilters/index.html
@@ -34,11 +34,11 @@ function filterform_cb() {
         }
     });
 
-    $(".submit").one('click', function(e) {
+    $(".submit").on('click', function(e) {
         var counters = "conds=" + $dc.fields_cnt + "&actions=" + $da.fields_cnt;
 
         simple_ajax_form_post(e, {
-            error_cb: filterform_cb,
+            formid: 'filterform',
             reload_mode: 'history',
             extradata: counters
         });
diff --git a/modoboa/extensions/sievefilters/views.py b/modoboa/extensions/sievefilters/views.py
index 31fce1b29..0352a23d4 100644
--- a/modoboa/extensions/sievefilters/views.py
+++ b/modoboa/extensions/sievefilters/views.py
@@ -9,7 +9,7 @@ from django.utils.translation import ugettext as _
 from django.core.urlresolvers import reverse
 from modoboa.lib import parameters
 from modoboa.lib.webutils import _render_error, \
-    ajax_response, ajax_simple_response
+    ajax_response, render_to_json_response
 from modoboa.lib.connections import ConnectionError
 from modoboa.extensions.admin.lib import needs_mailbox
 from .lib import SieveClient, SieveClientError
@@ -54,8 +54,12 @@ def index(request, tplname="sievefilters/index.html"):
 @needs_mailbox()
 def get_templates(request, ftype):
     if ftype == "condition":
-        return ajax_simple_response(FilterForm([], [], request).cond_templates)
-    return ajax_simple_response(FilterForm([], [], request).action_templates)
+        return render_to_json_response(
+            FilterForm([], [], request).cond_templates
+        )
+    return render_to_json_response(
+        FilterForm([], [], request).action_templates
+    )
 
 
 @login_required
@@ -87,8 +91,8 @@ def getfs(request, name):
 
     menu = '<ul id="fsetmenu" class="nav nav-list"><li class="nav-header">%s</li>%s</ul>' % \
         (_("Actions"), fset_menu(editormode, name))
-    resp = dict(status="ok", menu=menu, content=htmlcontent)
-    return ajax_simple_response(resp)
+    resp = dict(menu=menu, content=htmlcontent)
+    return render_to_json_response(resp)
 
 
 def build_filter_ctx(ctx, form):
@@ -119,13 +123,12 @@ def submitfilter(request, setname, okmsg, tplname, tplctx, update=False, sc=None
             fset.updatefilter(
                 oldname, fltname, conditions, actions, match_type
             )
-        try:
-            sc.pushscript(fset.name, str(fset))
-        except SieveClientError as e:
-            return ajax_response(request, "ko", respmsg=str(e))
-        return ajax_response(request, respmsg=okmsg, ajaxnav=True)
-    tplctx = build_filter_ctx(tplctx, form)
-    return ajax_response(request, status="ko", template=tplname, **tplctx)
+        sc.pushscript(fset.name, str(fset))
+        return render_to_json_response(okmsg)
+    #tplctx = build_filter_ctx(tplctx, form)
+    #return ajax_response(request, status="ko", template=tplname, **tplctx)
+
+    return render_to_json_response({'form_errors': form.errors}, status=400)
 
 
 @login_required
@@ -186,8 +189,8 @@ def removefilter(request, setname, fname):
     fset = sc.getscript(setname, format="fset")
     if fset.removefilter(fname.encode("utf-8")):
         sc.pushscript(fset.name, str(fset))
-        return ajax_response(request, respmsg=_("Filter removed"))
-    return ajax_response(request, "ko", respmsg=_("Failed to remove filter"))
+        return render_to_json_response(_("Filter removed"))
+    return render_to_json_response(_("Failed to remove filter"), status=500)
 
 
 @login_required
@@ -208,37 +211,28 @@ def savefs(request, name):
 @login_required
 @needs_mailbox()
 def new_filters_set(request, tplname="common/generic_modal_form.html"):
+    if request.method == "POST":
+        form = FiltersSetForm(request.POST)
+        if form.is_valid():
+            sc = SieveClient(user=request.user.username,
+                             password=request.session["password"])
+            sc.pushscript(form.cleaned_data["name"], "# Empty script",
+                          form.cleaned_data["active"])
+            return render_to_json_response({
+                "url": form.cleaned_data["name"],
+                "active": form.cleaned_data["active"],
+                "respmsg": _("Filters set created")
+            })
+        return render_to_json_response({'form_errors': form.errors}, status=400)
+
     ctx = {"title": _("Create a new filters set"),
            "formid": "newfiltersset",
            "action_label": _("Create"),
            "action_classes": "submit",
            "action": reverse(new_filters_set),
            "withmenu": False,
-           "withunseen": False}
-    if request.method == "POST":
-        form = FiltersSetForm(request.POST)
-        error = None
-        if form.is_valid():
-            sc = SieveClient(user=request.user.username,
-                             password=request.session["password"])
-            try:
-                sc.pushscript(form.cleaned_data["name"], "# Empty script",
-                              form.cleaned_data["active"])
-            except SieveClientError, e:
-                error = str(e)
-            else:
-                return ajax_simple_response({
-                    "status": "ok",
-                    "url": form.cleaned_data["name"],
-                    "active": form.cleaned_data["active"],
-                    "respmsg": _("Filters set created")
-                })
-
-        ctx["form"] = form
-        ctx["error"] = error
-        return ajax_response(request, status="ko", template=tplname, **ctx)
-
-    ctx["form"] = FiltersSetForm()
+           "withunseen": False,
+           "form": FiltersSetForm()}
     return render(request, tplname, ctx)
 
 
@@ -247,13 +241,10 @@ def new_filters_set(request, tplname="common/generic_modal_form.html"):
 def remove_filters_set(request, name):
     sc = SieveClient(user=request.user.username,
                      password=request.session["password"])
-    try:
-        sc.deletescript(name)
-    except SieveClientError, e:
-        return ajax_simple_response(dict(status="ko", respmsg=str(e)))
+    sc.deletescript(name)
     acs, scripts = sc.listscripts()
-    return ajax_simple_response(dict(
-        status="ok", respmsg=_("Filters set deleted"), newfs=acs
+    return render_to_json_response(dict(
+        respmsg=_("Filters set deleted"), newfs=acs
     ))
 
 
@@ -293,24 +284,19 @@ def toggle_filter_state(request, setname, fname):
                      password=request.session["password"])
     if type(fname) is unicode:
         fname = fname.encode("utf-8")
-    try:
-        fset = sc.getscript(setname, format="fset")
-        if fset.is_filter_disabled(fname):
-            ret = fset.enablefilter(fname)
-            newstate = _("yes")
-            color = "green"
-        else:
-            ret = fset.disablefilter(fname)
-            newstate = _("no")
-            color = "red"
-        if not ret:
-            pass
-        sc.pushscript(setname, str(fset))
-    except SieveClientError, e:
-        return ajax_response(request, "ko", respmsg=str(e))
-
-    return ajax_simple_response({
-        "status": "ok",
+    fset = sc.getscript(setname, format="fset")
+    if fset.is_filter_disabled(fname):
+        ret = fset.enablefilter(fname)
+        newstate = _("yes")
+        color = "green"
+    else:
+        ret = fset.disablefilter(fname)
+        newstate = _("no")
+        color = "red"
+    if not ret:
+        pass
+    sc.pushscript(setname, str(fset))
+    return render_to_json_response({
         "label": newstate,
         "color": color
     })
@@ -319,12 +305,9 @@ def toggle_filter_state(request, setname, fname):
 def move_filter(request, setname, fname, direction):
     sc = SieveClient(user=request.user.username,
                      password=request.session["password"])
-    try:
-        fset = sc.getscript(setname, format="fset")
-        fset.movefilter(fname.encode("utf-8"), direction)
-        sc.pushscript(setname, str(fset))
-    except (SieveClientError), e:
-        return ajax_response(request, "ko", respmsg=str(e))
+    fset = sc.getscript(setname, format="fset")
+    fset.movefilter(fname.encode("utf-8"), direction)
+    sc.pushscript(setname, str(fset))
     return ajax_response(
         request, template="sievefilters/guieditor.html", fs=fset
     )
diff --git a/modoboa/extensions/webmail/forms.py b/modoboa/extensions/webmail/forms.py
index fb0ba3729..aa6a0bb04 100644
--- a/modoboa/extensions/webmail/forms.py
+++ b/modoboa/extensions/webmail/forms.py
@@ -7,13 +7,20 @@ class ComposeMailForm(forms.Form):
     to = forms.CharField(label=_("To"))
     cc = forms.CharField(label=_("Cc"), required=False)
     cci = forms.CharField(label=_("Cci"), required=False)
-    subject = forms.CharField(label=_("Subject"), max_length=255, required=False)
+    subject = forms.CharField(
+        label=_("Subject"), max_length=255, required=False
+    )
+    origmsgid = forms.CharField(
+        label="", widget=forms.HiddenInput(), required=False
+    )
 
-    origmsgid = forms.CharField(label="", widget=forms.HiddenInput(), required=False)
 
 class FolderForm(forms.Form):
-    oldname = forms.CharField(label="", widget=forms.HiddenInput(), required=False)
+    oldname = forms.CharField(
+        label="", widget=forms.HiddenInput(), required=False
+    )
     name = forms.CharField()
 
+
 class AttachmentForm(forms.Form):
     attachment = forms.FileField(label=_("Select a file"))
diff --git a/modoboa/extensions/webmail/static/webmail/js/webmail.js b/modoboa/extensions/webmail/static/webmail/js/webmail.js
index 8ddd4c5b8..829c477ac 100644
--- a/modoboa/extensions/webmail/static/webmail/js/webmail.js
+++ b/modoboa/extensions/webmail/static/webmail/js/webmail.js
@@ -893,13 +893,12 @@ Webmail.prototype = {
         $("#mboxform").find("input").keypress(function(e) {
             if (e.which == 13) e.preventDefault();
         });
-        $(".submit").one('click', $.proxy(function(e) {
+        $(".submit").on('click', $.proxy(function(e) {
             var $link = $("#folders2 li.active").children("a");
 
             simple_ajax_form_post(e, {
                 reload_on_success: false,
                 formid: "mboxform",
-                error_cb: this.mboxform_cb,
                 extradata: ($link.length) ? "parent_folder=" + $link.attr("href") : "",
                 success_cb: $.proxy(this.mboxform_success, this)
             });
@@ -907,6 +906,7 @@ Webmail.prototype = {
     },
 
     mboxform_success: function(data) {
+        $("body").notify('success', data.respmsg, 2000);
         if (data.oldmb === undefined) {
             this.add_mailbox_to_tree(data.parent, data.newmb);
         } else if (data.newmb) {
diff --git a/modoboa/extensions/webmail/views.py b/modoboa/extensions/webmail/views.py
index 4c7c29257..5291f8a7a 100644
--- a/modoboa/extensions/webmail/views.py
+++ b/modoboa/extensions/webmail/views.py
@@ -12,7 +12,8 @@ from django.views.decorators.csrf import csrf_exempt
 from django.views.decorators.gzip import gzip_page
 from modoboa.lib import parameters
 from modoboa.lib.webutils import (
-    _render_to_string, ajax_response, ajax_simple_response
+    _render_to_string, ajax_response, ajax_simple_response,
+    render_to_json_response
 )
 from modoboa.extensions.admin.lib import needs_mailbox
 from .exceptions import WebmailError
@@ -132,6 +133,19 @@ def compact(request, name):
 def newfolder(request, tplname="webmail/folder.html"):
     mbc = IMAPconnector(user=request.user.username,
                         password=request.session["password"])
+
+    if request.method == "POST":
+        form = FolderForm(request.POST)
+        if form.is_valid():
+            pf = request.POST.get("parent_folder", None)
+            mbc.create_folder(form.cleaned_data["name"], pf)
+            return render_to_json_response({
+                'respmsg': _("Mailbox created"),
+                'newmb': form.cleaned_data["name"], 'parent': pf
+            })
+
+        return render_to_json_response({'form_errors': form.errors}, status=400)
+
     ctx = {"title": _("Create a new mailbox"),
            "formid": "mboxform",
            "action": reverse(newfolder),
@@ -140,24 +154,9 @@ def newfolder(request, tplname="webmail/folder.html"):
            "withunseen": False,
            "selectonly": True,
            "mboxes": mbc.getmboxes(request.user),
-           "hdelimiter": mbc.hdelimiter}
-
-    if request.method == "POST":
-        form = FolderForm(request.POST)
-        if form.is_valid():
-            pf = request.POST.get("parent_folder", None)
-            mbc.create_folder(form.cleaned_data["name"], pf)
-            return ajax_simple_response(dict(
-                status="ok", respmsg=_("Mailbox created"), 
-                newmb=form.cleaned_data["name"], parent=pf
-            ))
-
-        ctx["form"] = form
-        ctx["selected"] = None
-        return ajax_response(request, status="ko", template=tplname, **ctx)
-
-    ctx["form"] = FolderForm()
-    ctx["selected"] = None
+           "hdelimiter": mbc.hdelimiter,
+           "form": FolderForm(),
+           "selected": None}
     return render(request, tplname, ctx)
 
 
@@ -179,9 +178,10 @@ def editfolder(request, tplname="webmail/folder.html"):
         form = FolderForm(request.POST)
         if form.is_valid():
             pf = request.POST.get("parent_folder", None)
-            ctx["selected"] = pf
-            oldname, oldparent = separate_mailbox(request.POST["oldname"], sep=mbc.hdelimiter)
-            res = dict(status="ok", respmsg=_("Mailbox updated"))
+            oldname, oldparent = separate_mailbox(
+                request.POST["oldname"], sep=mbc.hdelimiter
+            )
+            res = {'respmsg': _("Mailbox updated")}
             if form.cleaned_data["name"] != oldname \
                     or (pf != oldparent):
                 newname = form.cleaned_data["name"] if pf is None \
@@ -193,21 +193,27 @@ def editfolder(request, tplname="webmail/folder.html"):
                 res["newparent"] = pf
                 if "mbox" in request.session:
                     del request.session["mbox"]
-            return ajax_simple_response(res)
+            return render_to_json_response(res)
 
-        ctx["mboxes"] = mbc.getmboxes(request.user)
-        ctx["form"] = form
-        return ajax_response(request, status="ko", template=tplname, **ctx)
+        return render_to_json_response({'form_errors': form.errors}, status=400)
 
     name = request.GET.get("name", None)
     if name is None:
         raise WebmailError(_("Invalid request"))
     shortname, parent = separate_mailbox(name, sep=mbc.hdelimiter)
-    ctx["mboxes"] = mbc.getmboxes(request.user, until_mailbox=parent)
-    ctx["form"] = FolderForm()
+    ctx = {"title": _("Edit mailbox"),
+           "formid": "mboxform",
+           "action": reverse(editfolder),
+           "action_label": _("Update"),
+           "action_classes": "submit",
+           "withunseen": False,
+           "selectonly": True,
+           "hdelimiter": mbc.hdelimiter,
+           "mboxes": mbc.getmboxes(request.user, until_mailbox=parent),
+           "form": FolderForm(),
+           "selected": parent}
     ctx["form"].fields["oldname"].initial = name
     ctx["form"].fields["name"].initial = shortname
-    ctx["selected"] = parent
     return render(request, tplname, ctx)
 
 
@@ -377,11 +383,11 @@ def render_compose(request, form, posturl, email=None, insert_signature=False):
         randid = set_compose_session(request)
 
     attachments = request.session["compose_mail"]["attachments"]
-    if len(attachments):
-        short_att_list = "(%s)" \
-            % ", ".join(map(lambda att: att["fname"],
-                            attachments[:2] + [{"fname": "..."}] \
-                                if len(attachments) > 2 else attachments))
+    if attachments:
+        short_att_list = "(%s)" % ", ".join(
+            [att['fname'] for att in (attachments[:2] + [{"fname": "..."}]
+             if len(attachments) > 2 else attachments)]
+        )
     else:
         short_att_list = ""
     content = _render_to_string(request, "webmail/compose.html", {
diff --git a/modoboa/lib/events.py b/modoboa/lib/events.py
index 66aa23270..b2e778bbb 100644
--- a/modoboa/lib/events.py
+++ b/modoboa/lib/events.py
@@ -91,7 +91,7 @@ class observe(object):
                         return []
                 else:
                     if not ext.enabled:
-                        return []
+                        return None
             elif not modname in settings.MODOBOA_APPS:
                 return []
             return f(*args, **kwargs)
@@ -144,7 +144,12 @@ def raiseQueryEvent(event, *args, **kwargs):
     if not event in events or not event in callbacks.keys():
         return result
     for callback in callbacks[event].values():
-        result += callback(*args, **kwargs)
+        tmp = callback(*args, **kwargs)
+        if tmp is None:
+            # Callback is registered but associated extension is
+            # disabled.
+            continue
+        result += tmp
     return result
 
 
@@ -158,10 +163,14 @@ def raiseDictEvent(event, *args):
     :return: a dictionnary
     """
     result = {}
-    if not event in events or not event in callbacks.keys():
+    if not event in events or not event in callbacks:
         return result
     for callback in callbacks[event].values():
         tmp = callback(*args)
+        if tmp is None:
+            # Callback is registered but associated extension is
+            # disabled.
+            continue
         for k, v in tmp.iteritems():
             result[k] = v
     return result
diff --git a/modoboa/lib/exceptions.py b/modoboa/lib/exceptions.py
index 026b72bd7..82c1135f0 100644
--- a/modoboa/lib/exceptions.py
+++ b/modoboa/lib/exceptions.py
@@ -8,10 +8,57 @@ from django.utils.translation import ugettext as _
 
 
 class ModoboaException(Exception):
-    pass
+    """
+    Base class for Modoboa custom exceptions.
+    """
+    http_code = None
+
+    def __init__(self, *args, **kwargs):
+        if 'http_code' in kwargs:
+            self.http_code = kwargs['http_code']
+            del kwargs['http_code']
+        super(ModoboaException, self).__init__(*args, **kwargs)
+
+
+class InternalError(ModoboaException):
+    """
+    Use this exception for system errors, missing dependencies, etc.
+    """
+    http_code = 500
+
+
+class BadRequest(ModoboaException):
+    """
+    Use this exception when received data doesn't validate a specific
+    format (example: wrong CSV line) or doesn't respect validation
+    rules.
+    """
+    http_code = 400
+
+
+class NotFound(ModoboaException):
+    """
+    Use this exception to indicate the requested resource could not be
+    found.
+    """
+    http_code = 404
+
+
+class Conflict(ModoboaException):
+    """
+    Use this exception to indicate that the request could not be
+    processed because of conflict in the request.
+    """
+    http_code = 409
 
 
 class PermDeniedException(ModoboaException):
+    """
+    Use this exception when a user tries to do something he is not
+    allowed to.
+    """
+    http_code = 403
+
     def __init__(self, msg=None):
         self.msg = msg
 
diff --git a/modoboa/lib/formutils.py b/modoboa/lib/formutils.py
index fa4e62cb3..f74fbec32 100644
--- a/modoboa/lib/formutils.py
+++ b/modoboa/lib/formutils.py
@@ -10,10 +10,20 @@ from django.utils.html import conditional_escape
 
 
 class CreationWizard(object):
-    def __init__(self, done_cb):
+    def __init__(self, done_cb=None):
         self.steps = []
         self.done_cb = done_cb
 
+    @property
+    def errors(self):
+        result = {}
+        for step in self.steps:
+            for name, value in step['form'].errors.items():
+                if name == '__all__':
+                    continue
+                result[name] = value
+        return result
+
     def add_step(self, cls, title, buttons, formtpl=None, new_args=None):
         self.steps += [dict(cls=cls, title=title, buttons=buttons,
                             formtpl=formtpl, new_args=new_args)]
@@ -33,19 +43,23 @@ class CreationWizard(object):
             return -1, _("Invalid request")
 
         stepid = stepid.replace("step", "")
-        stepid = int(stepid) - 1
-        if stepid < 0 or stepid >= len(self.steps):
+        stepid = int(stepid)
+        if stepid < 0 or stepid > len(self.steps):
             return -1, _("Invalid request")
         self.create_forms(request.POST)
-        if self.steps[stepid]["form"].is_valid():
-            if stepid == len(self.steps) - 1:
+        statuses = []
+        for cpt in xrange(0, stepid):
+            statuses.append(self.steps[cpt]["form"].is_valid())
+        if False in statuses:
+            return 0, stepid
+        if stepid == len(self.steps):
+            if self.done_cb is not None:
                 self.done_cb(self.steps)
-                return 2, None
-            return 1, stepid
-        return 0, stepid
+            return 2, None
+        return 1, stepid
 
     def get_title(self, stepid):
-        return "%d. %s" % (stepid + 1, self.steps[stepid]["title"])
+        return "%d. %s" % (stepid, self.steps[stepid - 1]["title"])
 
 
 class DynamicForm(object):
@@ -109,6 +123,16 @@ class TabForms(object):
     def _before_is_valid(self, form):
         return True
 
+    @property
+    def errors(self):
+        result = {}
+        for f in self.forms:
+            for name, value in f['instance'].errors.items():
+                if name == '__all__':
+                    continue
+                result[name] = value
+        return result
+    
     def is_valid(self, mandatory_only=False, optional_only=False):
         to_remove = []
         for f in self.forms:
diff --git a/modoboa/lib/middleware.py b/modoboa/lib/middleware.py
index 7b7fc1f15..44f08dd07 100644
--- a/modoboa/lib/middleware.py
+++ b/modoboa/lib/middleware.py
@@ -3,7 +3,9 @@ import re
 from django.http import Http404, HttpResponseRedirect
 from modoboa.core.models import Extension
 from modoboa.core.extensions import exts_pool
-from modoboa.lib.webutils import _render_error, ajax_response
+from modoboa.lib.webutils import (
+    _render_error, ajax_response, render_to_json_response
+)
 from modoboa.lib.exceptions import ModoboaException
 
 
@@ -41,6 +43,10 @@ class CommonExceptionCatcher(object):
             return _render_error(
                 request, user_context=dict(error=str(exception))
             )
-        return ajax_response(
-            request, status="ko", respmsg=unicode(exception), norefresh=True
+        if exception.http_code is None:
+            return ajax_response(
+                request, status="ko", respmsg=unicode(exception), norefresh=True
+            )
+        return render_to_json_response(
+            unicode(exception), status=exception.http_code
         )
diff --git a/modoboa/lib/parameters.py b/modoboa/lib/parameters.py
index 97a3ab270..61d3372d7 100644
--- a/modoboa/lib/parameters.py
+++ b/modoboa/lib/parameters.py
@@ -11,9 +11,9 @@ Only super users will be able to access this part of the web interface.
 import inspect
 import re
 from django import forms
+from . import events
 from exceptions import ModoboaException
 
-
 _params = {'A': {}, 'U': {}}
 
 
@@ -28,7 +28,12 @@ class NotDefined(ModoboaException):
 
 
 class GenericParametersForm(forms.Form):
+    """Base class for parameter forms.
+
+    Each extension has the possibility to define global parameters.
+    """
     app = None
+    visibility_rules = None
 
     def __init__(self, *args, **kwargs):
         if self.app is None:
@@ -38,10 +43,12 @@ class GenericParametersForm(forms.Form):
         super(GenericParametersForm, self).__init__(*args, **kwargs)
 
         self.visirules = {}
-        if hasattr(self, "visibility_rules"):
+        if self.visibility_rules is not None:
             for key, rule in self.visibility_rules.items():
                 field, value = rule.split("=")
-                visibility = {"field": "id_%s-%s" % (self.app, field), "value": value}
+                visibility = {
+                    "field": "id_%s-%s" % (self.app, field), "value": value
+                }
                 self.visirules["%s-%s" % (self.app, key)] = visibility
 
         if not args:
@@ -50,6 +57,11 @@ class GenericParametersForm(forms.Form):
     def _load_initial_values(self):
         raise NotImplementedError
 
+    def _load_extra_parameters(self, level):
+        params = events.raiseDictEvent('GetExtraParameters', self.app, level)
+        for pname, pdef in params.items():
+            self.fields[pname] = pdef
+
     def _save_parameter(self, p, name, value):
         if p.value == value:
             return
@@ -101,6 +113,7 @@ class AdminParametersForm(GenericParametersForm):
                 pass
         return values
 
+
 class UserParametersForm(GenericParametersForm):
     def __init__(self, *args, **kwargs):
         self.user = kwargs.pop("user") if "user" in kwargs else None
diff --git a/modoboa/lib/permissions.py b/modoboa/lib/permissions.py
index ce5dcb9d7..8b93a2d8c 100644
--- a/modoboa/lib/permissions.py
+++ b/modoboa/lib/permissions.py
@@ -18,7 +18,9 @@ def get_account_roles(user):
     std_roles = [("SimpleUsers", _("Simple user"))]
     if user.is_superuser:
         std_roles += [("SuperAdmins",  _("Super administrator"))]
-    if user.has_perm("admin.add_domain"):
+    filters = events.raiseQueryEvent('UserCanSetRole', user, 'DomainAdmins')
+    if user.has_perm("admin.add_domain") and \
+            (not filters or True in filters):
         std_roles += [("DomainAdmins", _("Domain administrator"))]
     std_roles += events.raiseQueryEvent("GetExtraRoles", user)
     return sorted(std_roles, key=lambda role: role[1])
diff --git a/modoboa/lib/singleton.py b/modoboa/lib/singleton.py
new file mode 100644
index 000000000..3fd8f0c17
--- /dev/null
+++ b/modoboa/lib/singleton.py
@@ -0,0 +1,15 @@
+
+
+# works in Python 2 & 3
+class _Singleton(type):
+    _instances = {}
+
+    def __call__(cls, *args, **kwargs):
+        if cls not in cls._instances:
+            cls._instances[cls] = \
+                super(_Singleton, cls).__call__(*args, **kwargs)
+        return cls._instances[cls]
+
+
+class Singleton(_Singleton('SingletonMeta', (object,), {})):
+    pass
diff --git a/modoboa/lib/tests.py b/modoboa/lib/tests.py
index 0a0330294..8601f8682 100644
--- a/modoboa/lib/tests.py
+++ b/modoboa/lib/tests.py
@@ -13,20 +13,17 @@ class ModoTestCase(TestCase):
         self.clt = Client()
         self.assertEqual(self.clt.login(username=username, password=password), True)
 
-    def check_ajax_request(self, method, url, params, status="ok", **kwargs):
+    def ajax_request(self, method, url, params, status=200):
         response = getattr(self.clt, method) \
             (url, params, HTTP_X_REQUESTED_WITH='XMLHttpRequest')
-        self.assertEqual(response.status_code, 200)
-        obj = simplejson.loads(response.content)
-        self.assertEqual(obj["status"], status)
-        for kw, v in kwargs.items():
-            self.assertEqual(obj[kw], v)
+        self.assertEqual(response.status_code, status)
+        return simplejson.loads(response.content)
 
-    def check_ajax_post(self, *args, **kwargs):
-        self.check_ajax_request("post", *args, **kwargs)
+    def ajax_post(self, *args, **kwargs):
+        return self.ajax_request('post', *args, **kwargs)
 
-    def check_ajax_get(self, *args, **kwargs):
-        self.check_ajax_request("get", *args, **kwargs)
+    def ajax_get(self, *args, **kwargs):
+        return self.ajax_request('get', *args, **kwargs)
 
 
 class ExtTestCase(ModoTestCase):
diff --git a/modoboa/static/js/confirmation.js b/modoboa/static/js/confirmation.js
index 59bd9314d..3d6296be9 100644
--- a/modoboa/static/js/confirmation.js
+++ b/modoboa/static/js/confirmation.js
@@ -87,29 +87,25 @@
                  }
                  params += $(this).attr("name") + "=true";
              });
-
              $.ajax({
                  cache: false,
                  method: this.options.method,
                  data: params,
-                 url: this.$element.attr('href'),
-                 complete: $.proxy(function(XMLHttpRequest, textStatus) {
-                     var data;
-                     try {
-                         data = $.parseJSON(XMLHttpRequest.responseText);
-                     } catch (e) {
-                         data = { status: 'ko', respmsg: gettext('Internal Error') };
-                     }
-                     if (data.status == "ok") {
-                         if (this.options.success_cb != undefined) {
-                             this.options.success_cb(data);
-                             return;
-                         }
-                         window.location.reload();
-                     } else {
-                         $("body").notify("error", data.respmsg);
-                     }
-                 }, this)
+                 url: this.$element.attr('href')
+             }).done($.proxy(function(data) {
+                 if (this.options.success_cb != undefined) {
+                     this.options.success_cb(data);
+                     return;
+                 }
+                 window.location.reload();
+             }, this)).fail(function(jqxhr) {
+                 var data;
+                 try {
+                     data = $.parseJSON(jqxhr.responseText);
+                 } catch (e) {
+                     data = gettext('Internal Error');
+                 }
+                 $("body").notify("error", data);
              });
              this.box.remove();
          }
diff --git a/modoboa/static/js/creation_wizard.js b/modoboa/static/js/creation_wizard.js
index 25c4d2cce..a04e4bb82 100644
--- a/modoboa/static/js/creation_wizard.js
+++ b/modoboa/static/js/creation_wizard.js
@@ -12,6 +12,7 @@
             this.$element.carousel({pause: true});
             this.$element.carousel("pause");
             this.listen();
+            this.titles = {};
             $('input:text:visible:first').focus();
         },
 
@@ -21,16 +22,28 @@
             $(".submit").on("click", $.proxy(this.submit, this));
         },
 
+        get_current_step_id: function() {
+            return $(".item.active").attr("id");
+        },
+
+        get_current_title: function() {
+            return $(".modal-header").find("small").html();
+        },
+
+        set_current_title: function(title) {
+            $(".modal-header").find("small").html(title);
+        },
+
         post: function(last) {
             var $form = (this.options.formid) ? $('#' + this.options.formid) : $('form');
-            var data = $form.serialize() + "&stepid=" + $(".item.active").attr("id");
+            var data = $form.serialize() + "&stepid=" + this.get_current_step_id();
 
-            $.post($form.attr("action"), data, $.proxy(function(resp) {
-                if (resp.status == "ok") {
+            $.ajax({type: 'POST', url: $form.attr("action"), data: data})
+                .done($.proxy(function(resp) {
                     if (!last) {
                         var stepid = resp.stepid + 1;
                         $('input:text:visible:first').focus();
-                        $(".modal-header").find("small").html(resp.title);
+                        this.set_current_title(resp.title);
                         if (this.options.transition_callbacks[stepid] != undefined) {
                             this.options.transition_callbacks[stepid]();
                         }
@@ -43,20 +56,23 @@
                             window.location.reload();
                         }
                     }
-                    return;
-                }
-                if (resp.stepid != undefined && resp.form != undefined) {
-                    var stepid = resp.stepid + 1;
-                    $("#step" + stepid).html(resp.form);
-                    if (this.options.error_callbacks[stepid] != undefined) {
-                        this.options.error_callbacks[stepid]();
+                }, this))
+                .fail($.proxy(function(jqxhr) {
+                    var resp = $.parseJSON(jqxhr.responseText);
+                    if (resp.stepid != undefined) {
+                        var stepid = resp.stepid;
+                        display_form_errors("step" + stepid, resp);
+                        if (this.options.error_callbacks[stepid] != undefined) {
+                            this.options.error_callbacks[stepid]();
+                        }
+                        $('input:text:visible:first').focus();
+                        if (resp.respmsg) {
+                            $(".modal-body").prepend(build_error_alert(resp.respmsg));
+                        }
+                        return;
                     }
-                    $('input:text:visible:first').focus();
-                }
-                if (resp.respmsg) {
-                    $(".modal-body").prepend(build_error_alert(resp.respmsg));
-                }
-            }, this));
+                    $(".modal-body").prepend(build_error_alert(resp));
+                }, this));
         },
 
         update_buttons: function() {
@@ -66,6 +82,8 @@
 
         next: function(evt) {
             evt.preventDefault();
+            var step_id = this.get_current_step_id();
+            this.titles[step_id] = this.get_current_title();
             this.$element.on('slid', this.update_buttons);
             this.post(false);
         },
@@ -74,6 +92,7 @@
             evt.preventDefault();
             this.$element.on('slid', this.update_buttons);
             this.$element.carousel('prev');
+            this.set_current_title(this.titles[this.get_current_step_id()]);
         },
 
         submit: function(evt) {
@@ -98,7 +117,8 @@
     };
 
     $.fn.cwizard.defaults = {
-        transition_callbacks: {}
+        transition_callbacks: {},
+        error_callbacks: {}
     };
 
 })(jQuery);
\ No newline at end of file
diff --git a/modoboa/static/js/global.js b/modoboa/static/js/global.js
index 1016c0672..5b28f076b 100644
--- a/modoboa/static/js/global.js
+++ b/modoboa/static/js/global.js
@@ -31,8 +31,11 @@ function modalbox(e, css, defhref, defcb, defclosecb) {
         $(href).modal('open');
         return;
     }
-    $.get(href, function(data) {
+    $.ajax({type: "GET", url: href}).done(function(data) {
         if (typeof data === "object") {
+            /*
+             * Compatibility with the old way...
+             */
             if (data.status == "ko" && data.respmsg) {
                 $("body").notify("error", data.respmsg);
             }
@@ -67,6 +70,9 @@ function modalbox(e, css, defhref, defcb, defclosecb) {
         if (css != undefined) {
             $div.css(css);
         }
+    }).fail(function(jqxhr) {
+        var data = $.parseJSON(jqxhr.responseText);
+        $("body").notify("error", data);
     });
 }
 
@@ -111,57 +117,46 @@ if (!Object.keys) {
 }
 
 /*
- * Simple function that sends a form using an 'ajax' post request.
- *
- * The function is intended to be used in a modal environment.
+ * Clean all errors in a given form.
  */
-function simple_ajax_form_post(e, options) {
-    e.preventDefault();
-    var $form = (options.formid !== undefined) ? $("#" + options.formid) : $("form");
-    var defaults = {reload_on_success: true, reload_mode: 'full', modal: true};
-    var opts = $.extend({}, defaults, options);
-    var args = $form.serialize();
+function clean_form_errors(formid) {
+    $("#" + formid + " div.error").removeClass("error");
+    $("#" + formid + " span.help-inline").remove();
+}
 
-    if (options.extradata != undefined) {
-        args += "&" + options.extradata;
-    }
-    $.post($form.attr("action"), args, function(data) {
-        if (data.status == "ok") {
-            $("#modalbox").modal('hide');
-            if (opts.success_cb != undefined) {
-                opts.success_cb(data);
-                return;
-            }
-            if (opts.reload_on_success) {
-                if (opts.reload_mode == 'full') {
-                    window.location.reload();
-                } else {
-                    history.update(true);
-                }
-            }
-            if (data.respmsg) {
-                $("body").notify('success', data.respmsg, 2000);
-            }
+/*
+ * Display validation errors for a given form.
+ */
+function display_form_errors(formid, data) {
+    clean_form_errors(formid);
+    $.each(data.form_errors, function(id, value) {
+        var fullid = "id_" + (data.prefix ? data.prefix + "-" : "") + id;
+        var $widget = $("#" + formid + " #" + fullid);
+        var spanid = fullid + "-error";
+        var $span = $("#" + spanid);
+
+        if (!$widget.parents(".control-group").hasClass("error")) {
+            $widget.parents(".control-group").addClass("error");
+        }
+        if (!$span.length) {
+            $span = $("<span />", {
+                "class": "help-inline",
+                "html": value[0],
+                "id": spanid
+            });
+            $widget.parents(".controls").append($span);
         } else {
-            if (opts.modal) {
-                if (data.content != "") {
-                    $('.modal').html(data.content);
-                }
-                if (data.respmsg) {
-                    $('.modal-body').prepend(build_error_alert(data.respmsg));
-                }
-            }
-            if (opts.error_cb != undefined) {
-                opts.error_cb(data);
-            }
+            $span.html(value[0]);
         }
     });
 }
 
 /*
- * Replacement
+ * Simple function that sends a form using an 'ajax' post request.
+ *
+ * The function is intended to be used in a modal environment.
  */
-function simple_ajax_form_post2(e, options) {
+function simple_ajax_form_post(e, options) {
     e.preventDefault();
     var $form = (options.formid != undefined) ? $("#" + options.formid) : $("form");
     var defaults = {reload_on_success: true, reload_mode: 'full', modal: true};
@@ -176,7 +171,9 @@ function simple_ajax_form_post2(e, options) {
         url: $form.attr("action"),
         data: args
     }).done(function(data) {
-        $("#modalbox").modal('hide');
+        if (opts.modal) {
+            $("#modalbox").modal('hide');
+        }
         if (opts.success_cb != undefined) {
             opts.success_cb(data);
             return;
@@ -188,38 +185,22 @@ function simple_ajax_form_post2(e, options) {
                 history.update(true);
             }
         }
-        if (data.respmsg) {
-            $("body").notify('success', data.respmsg, 2000);
+        if (data) {
+            $("body").notify('success', data, 2000);
         }
     }).fail(function(jqxhr) {
-        if (jqxhr.status != 400) {
-            return;
-        }
-        var result = $.parseJSON(jqxhr.responseText);
-        $("div.error").removeClass("error");
-        $("span.help-inline").remove();
-        $.each(result, function(id, value) {
-            var fullid = "id_" + id;
-            var $widget = $("#" + fullid);
-            var spanid = fullid + "-error";
-            var $span = $("#" + spanid);
-
-            if (!$widget.parents(".control-group").hasClass("error")) {
-                $widget.parents(".control-group").addClass("error");
-            }
-            if (!$span.length) {
-                $span = $("<span />", {
-                    "class": "help-inline",
-                    "html": value[0],
-                    "id": spanid
-                });
-                $widget.parents(".controls").append($span);
+        var data = $.parseJSON(jqxhr.responseText);
+        if (data.form_errors) {
+            display_form_errors(options.formid, data);
+        } else {
+            if (opts.modal) {
+                $('.modal-body').prepend(build_error_alert(data));
             } else {
-                $span.html(value[0]);
+                $('body').notify('error', data);
             }
-        });
+        }
         if (opts.error_cb) {
-            opts.error_cb(result);
+            opts.error_cb(data);
         }
     });
 }
diff --git a/modoboa/static/js/twocols_nav.js b/modoboa/static/js/twocols_nav.js
index d8d3ed337..8c955c2f4 100644
--- a/modoboa/static/js/twocols_nav.js
+++ b/modoboa/static/js/twocols_nav.js
@@ -25,41 +25,11 @@ TwocolsNav.prototype = {
                 formid: this.options.formid,
                 modal: false,
                 reload_on_success: false,
-                error_cb: $.proxy(this.display_errors, this),
                 success_cb: $.proxy(this.save_cb, this)
             });
         }, this));
     },
 
-    display_errors: function(data) {
-        if (data.errors === undefined || !data.errors.length) {
-            if (data.respmsg) {
-                $("body").notify("error", data.respmsg);
-            }
-            return;
-        }
-        $.each(data.errors, function(id, value) {
-            var fullid = "id_" + (data.prefix ? data.prefix + "-" : "") + id;
-            var $widget = $("#" + fullid);
-            var spanid = fullid + "-error";
-            var $span = $("#" + spanid);
-
-            if (!$widget.parents(".control-group").hasClass("error")) {
-                $widget.parents(".control-group").addClass("error");
-            }
-            if (!$span.length) {
-                $span = $("<span />", {
-                    "class": "help-inline",
-                    "html": value[0],
-                    "id": spanid
-                });
-                $widget.parents(".controls").append($span);
-            } else {
-                $span.html(value[0]);
-            }
-        });
-    },
-
     update_content: function(data) {
         if (data.content) {
             $('#' + this.options.divid).html(data.content);
@@ -134,6 +104,7 @@ TwocolsNav.prototype = {
     },
 
     save_cb: function(data) {
+        clean_form_errors(this.options.formid);
         if (this.options.reload_exceptions) {
             for (var i = 0; i < this.options.reload_exceptions.length; i++) {
                 if (this.navobj.getbaseurl() == this.options.reload_exceptions[i]) {
@@ -142,7 +113,7 @@ TwocolsNav.prototype = {
                 }
             }
         }
-        $("body").notify("success", data.respmsg, 2000);
+        $("body").notify("success", data, 2000);
     },
 
     load_section: function(e) {