      */ 
     private function enterFrameHandler(event:Event):void
     {
-        navigator.removeEventListener(Event.ENTER_FRAME, enterFrameHandler);
+        if (event)
+            navigator.removeEventListener(Event.ENTER_FRAME, enterFrameHandler);
+        
         effect = null;
-        
         transitionComplete();
     }
     

     */ 
    private var verticalTransition:Boolean;
    
    
    //--------------------------------------------------------------------------
    //

        if (!consolidatedTransition)
            actionBarMoveEffect_effectUpdateHandler(null);
        
        if (renderLastFrame)
        {
            // We don't call transitionComplete just yet, we want to ensure
            // that the last frame of animation actually gets rendered on screen
            // before we clean up after ourselves.  This prevents a perceived 
            // stutter on the very last frame.
            navigator.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
        }
        else
        {
            enterFrameHandler(null);
        }
    }
    
    /**
