         if (!virtualLayoutUnderway)
             super.invalidateSize();
     }
-       
+
     /**
      *  @private 
      *  Make sure there's a typicalLayoutElement for virtual layout.
      */
     override protected function measure():void
     {
-        if (layout && layout.virtualLayout)
+        if (layout && layout.useVirtualLayout)
             ensureTypicalLayoutElement();
         super.measure();
     }


        _layeringFlags &= ~LAYERING_DIRTY;
        
        var len:int = numLayoutElements;
        for (var i:int = 0; i < len; i++)
        {  
            var myItemRenderer:IVisualElement = getRendererForItemAt(i);
            var layer:Number = myItemRenderer.layer;
            
            if (layer != 0)

        var myItemRenderer:IVisualElement = itemToRenderer[item];
        delete itemToRenderer[item];
        
        dispatchEvent(new RendererExistenceEvent(
                      RendererExistenceEvent.RENDERER_REMOVE, false, false, 
                      myItemRenderer, index, item));
        
        // If the item and renderer are different objects, set the renderer data to 
        // null here to clear it out. Otherwise, the renderer keeps a reference to the item,
