diff --git a/modoboa/admin/models.py b/modoboa/admin/models.py
index 78c9bfd50..07634b07d 100644
--- a/modoboa/admin/models.py
+++ b/modoboa/admin/models.py
@@ -760,24 +760,24 @@ class Mailbox(DatesAware):
         return True
 
     @staticmethod
-    def resolve_uid(value):
+    def resolve_id(value, idname, errmsg):
         if value.isdigit():
             return value
         try:
-            uid = pwd.getpwnam(value).pw_uid
+            rid = getattr(pwd.getpwnam(value), idname)
         except KeyError:
-            raise AdminError(_("%s is not a valid uid/username" % value))
-        return uid
+            raise AdminError(errmsg)
+        return rid
+
+    @staticmethod
+    def resolve_uid(value):
+        err = _("%s is not a valid uid/username" % value)
+        return Mailbox.resolve_id(value, "pw_uid", err)
 
     @staticmethod
     def resolve_gid(value):
-        if value.isdigit():
-            return value
-        try:
-            gid = pwd.getpwnam(value).pw_gid
-        except KeyError:
-            raise AdminError(_("%s is not a valid gid/groupname" % value))
-        return gid
+        err = _("%s is not a valid gid/groupname" % value)
+        return Mailbox.resolve_id(value, "pw_gid", err)
 
     def set_ownership(self):
         """Set uid and gid for this mailbox
diff --git a/modoboa/admin/templates/admin/parameters.html b/modoboa/admin/templates/admin/parameters.html
index 3cbf6ac3e..ec810251c 100644
--- a/modoboa/admin/templates/admin/parameters.html
+++ b/modoboa/admin/templates/admin/parameters.html
@@ -1,7 +1,7 @@
-{% load i18n %}
+{% load i18n %}{% load url from future %}
 {% url "modoboa.admin.views.saveparameters" as action %}
 <h2>{% trans "Parameters" %} <small>{% trans "Configure Modoboa" %}</small></h2><hr />
-<form id="settings_form" method="POST" action="{{ action }}" class="form-horizontal">
+<form id="settings_form" method="POST" action="{% url 'modoboa.admin.views.saveparameters' %}" class="form-horizontal">
   {% include "common/parameters.html" %}
 </form>
 <hr>
diff --git a/modoboa/static/js/twocols_nav.js b/modoboa/static/js/twocols_nav.js
index f15c487a6..4975fee1c 100644
--- a/modoboa/static/js/twocols_nav.js
+++ b/modoboa/static/js/twocols_nav.js
@@ -33,10 +33,15 @@ TwocolsNav.prototype = {
     },
 
     update_content: function(data) {
-        $('#' + this.options.divid).html(data.content);
+        if (data.content) {
+            $('#' + this.options.divid).html(data.content);
+        }
         if (data.onload_cb) {
             eval(data.onload_cb + '()');
         }
+        if (data.respmsg) {
+            $("body").notify("error", data.respmsg);
+        }
         $('#' + this.options.divid + ' select').change($.proxy(this.select_change, this));
         $(".help").popover().click(function(e) {e.preventDefault();});
         $('#' + this.options.divid + ' select').change();