          */
         public function get maxVerticalScrollPosition():Number
         {
-            return ScrollBarModel(vScrollBar.model).maximum - 
-                ScrollBarModel(vScrollBar.model).pageSize;
+            return _vScrollBarModel.maximum - 
+                _vScrollBarModel.pageSize;
         }
         
     

         */
        public function get verticalScrollPosition():Number
        {
            return ScrollBarModel(vScrollBar.model).value;
        }
        
        /**

         */
        public function set verticalScrollPosition(value:Number):void
        {
            _vScrollBarModel.value = value;
        }

        /**
