         
         if (instance == verticalScrollBar)
             verticalScrollBar.viewport = null;
-        
         else if (instance == horizontalScrollBar)
             horizontalScrollBar.viewport = null;
     }

    override protected function attachSkin():void
    {
        super.attachSkin();
        Group(skin).layout = new ScrollerLayout();
        installViewport();
        skin.addEventListener(MouseEvent.MOUSE_WHEEL, skin_mouseWheelHandler);


import mx.core.EventPriority;
import mx.core.FlexGlobals;
import mx.core.IFactory;
import mx.core.IInvalidating;
import mx.core.IVisualElement;
import mx.core.IVisualElementContainer;
