     
     private function uninstallViewport():void
     {
-    	if (skinObject && viewport)
+    	if (skin && viewport)
     	{
-    		skinObject.removeItem(viewport);
+    		skin.removeItem(viewport);
     		viewport.removeEventListener(PropertyChangeEvent.PROPERTY_CHANGE, viewport_propertyChangeHandler);
     	}
     }


    private function installViewport():void
    {
        if (skinObject && viewport)
        {
            skinObject.addItemAt(viewport, 0);
            viewport.addEventListener(PropertyChangeEvent.PROPERTY_CHANGE, viewport_propertyChangeHandler);
        }
 	

    
    private function invalidateSkin():void
    {
        if (skin)
        {
            skin.invalidateSize()
            skin.invalidateDisplayList();
        }
    }    
    
