Index: trunk/core/units/categories/categories_event_handler.php
===================================================================
diff -u -r8472 -r8491
--- trunk/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 8472)
+++ trunk/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 8491)
@@ -30,6 +30,13 @@
 				// allow sorting on front event without view permission
 				return true;
 			}
+
+			if ($event->Name == 'OnItemBuild') {
+				$category_id = $this->getPassedID($event);
+				if ($category_id == 0) {
+					return true;
+				}
+			}
 		}
 
 		if ($event->Name == 'OnEdit' || $event->Name == 'OnSave') {