diff --git a/UI/Common/UIxAclEditor.h b/UI/Common/UIxAclEditor.h
index e4d0b1d35..72a34dbaf 100644
--- a/UI/Common/UIxAclEditor.h
+++ b/UI/Common/UIxAclEditor.h
@@ -29,7 +29,7 @@
 {
   BOOL prepared;
   BOOL publishInFreeBusy;
-  NSArray *acls;
+  NSArray *aclUsers;
   NSArray *savedUIDs;
   NSMutableArray *users;
   NSString *currentUser;
diff --git a/UI/Common/UIxAclEditor.m b/UI/Common/UIxAclEditor.m
index e0328ace9..e87a15259 100644
--- a/UI/Common/UIxAclEditor.m
+++ b/UI/Common/UIxAclEditor.m
@@ -29,6 +29,7 @@
 #import <SoObjects/SOGo/LDAPUserManager.h>
 #import <SoObjects/SOGo/SOGoContentObject.h>
 #import <SoObjects/SOGo/SOGoPermissions.h>
+#import <SoObjects/SOGo/NSArray+Utilities.h>
 
 #import "UIxAclEditor.h"
 
@@ -38,7 +39,7 @@
 {
   if ((self = [super init]))
     {
-      acls = nil;
+      aclUsers = nil;
       prepared = NO;
       publishInFreeBusy = NO;
       users = [NSMutableArray new];
@@ -59,10 +60,10 @@
 
 - (NSArray *) aclsForObject
 {
-  if (!acls)
-    acls = [[self clientObject] acls];
+  if (!aclUsers)
+    aclUsers = [[self clientObject] aclUsers];
 
-  return acls;
+  return aclUsers;
 }
 
 - (NSString *) _displayNameForUID: (NSString *) uid
@@ -92,24 +93,20 @@
 - (void) _prepareUsers
 {
   NSEnumerator *aclsEnum;
-  NSDictionary *currentAcl;
   NSString *currentUID, *ownerLogin;
 
   ownerLogin = [[self clientObject] ownerInContext: context];
 
   aclsEnum = [[self aclsForObject] objectEnumerator];
-  currentAcl = [aclsEnum nextObject];
-  while (currentAcl)
+  currentUID = [aclsEnum nextObject];
+  while (currentUID)
     {
-      currentUID = [currentAcl objectForKey: @"c_uid"];
       if (!([currentUID isEqualToString: ownerLogin]
-	    || [currentUID isEqualToString: SOGoDefaultUserID]
-	    || [users containsObject: currentUID]))
-	  [users addObject: currentUID];
-      currentAcl = [aclsEnum nextObject];
-
-      prepared = YES;
+	    || [currentUID isEqualToString: SOGoDefaultUserID]))
+	[users addObjectUniquely: currentUID];
+      currentUID = [aclsEnum nextObject];
     }
+  prepared = YES;
 }
 
 - (NSArray *) usersForObject
diff --git a/UI/WebServerResources/UIxAclEditor.js b/UI/WebServerResources/UIxAclEditor.js
index 74845b325..0745c2fe0 100644
--- a/UI/WebServerResources/UIxAclEditor.js
+++ b/UI/WebServerResources/UIxAclEditor.js
@@ -119,7 +119,9 @@ function onOpenUserRights(event) {
 
 function onAclLoadHandler() {
    defaultUserID = $("defaultUserID").value;
-   Event.observe($("defaultRolesBtn"), "click", openRightsForDefaultUser);
+   var defaultRolesBtn = $("defaultRolesBtn");
+   if (defaultRolesBtn)
+      Event.observe(defaultRolesBtn, "click", openRightsForDefaultUser);
    var ul = $("userList");
    var lis = ul.childNodesWithTag("li");
    for (var i = 0; i < lis.length; i++)