      */
     public function addItemAt(item:Object, index:int):void
     {
-    	addChildAt(item as DisplayObject, index);
+        addChildAt(item as DisplayObject, index);
     }
 
     /**

     */
    public function addItem(item:Object):void
    {
    	addChild(item as DisplayObject);
    }

    /**

 *  for selecting which child container is currently visible.
 *  Typically, you set its <code>selectedIndex</code> or
 *  <code>selectedChild</code> property in ActionScript in response to
 *  some user action. 
 *  Alternately, you can associate an MX LinkBar, TabBar, ButtonBar, or ToggleButtonBar
 *  control or a Spark ButtonBar control with a ViewStack container to provide a navigation interface.
 *  To do so, specify the ViewStack container as the value of the
 *  <code>dataProvider</code> property of the LinkBar, TabBar or
 *  ToggleButtonBar container.</p>
