     /**
      *  @inheritDoc
      */
-    public function addElement(element:Object):Object
+    public function addElement(element:IVisualElement):IVisualElement
     {
         return addElementAt(element, numElements);
     }

        var n:int = numElements;
        for (var i:int = 0; i < n; i++)
        {
            var child:Object = getItemAt(i);

            if ( recursive && child is IStyleClient)
            {

    private var mxmlContentChanged:Boolean = false;
    private var needsDisplayObjectAssignment:Boolean = false;
    
    private var _mxmlContent:Array;
    private var layeringMode:uint = ITEM_ORDERED_LAYERING;
    private var numGraphicElements:uint = 0;
    
    private static const ITEM_ORDERED_LAYERING:uint = 0;
    private static const SPARSE_LAYERING:uint = 1;
    
    //----------------------------------
    //  alpha
