      *  Creates a clip mask with the specified dimensions.
      */
     mx_internal function createItemMask(x:Number, y:Number,
-                                    width:Number, height:Number):DisplayObject
+                width:Number, height:Number, contentHolder:DisplayObjectContainer = null):DisplayObject
     {
         var mask:Shape;
 


            default:
            {
                if (findKey(event.keyCode))
                    event.stopPropagation();
            }
        }

                        break;
                    }
                    
                }
                try
                {
