 import mx.core.IDataRenderer;
 import mx.core.IDeferredInstance;
 import mx.core.IFactory;
+import mx.core.mx_internal;
 import mx.core.UIComponent;
 import mx.events.CollectionEvent;
 import mx.events.CollectionEventKind

                itemAdded(_dataProvider.getItemAt(i), i);
            }
        }
        
        /* if (maskElements)
        {
            for (var k:Object in maskElements)
            {
                var maskElement:DisplayObject = k as DisplayObject;
                if (maskElement && (!maskElement.parent || maskElement.parent !== this))
                {
                    super.addChild(maskElement);
                    var maskComp:UIComponent = maskElement as UIComponent;
                    if (maskComp)
                    {
                        maskComp.validateNow();
                        maskComp.setActualSize(maskComp.getExplicitOrMeasuredWidth(), 
                                               maskComp.getExplicitOrMeasuredHeight());
                    }
                    
                    var maskTarget:IGraphicElement = maskElements[k] as IGraphicElement;
                    if (maskTarget)
                    {
                        maskTarget.applyMask();
                    }
                }
            }
        } */
    }
    
    /**

    }
    
    /**
     *  @inheritDoc
     */
    override public function addChild(child:DisplayObject):DisplayObject
