 
 package spark.components
 {
+import mx.core.ILayoutElement;
+import mx.events.PropertyChangeEvent;
+import mx.events.ResizeEvent;
+
 import spark.components.supportClasses.ScrollBar;
-import mx.core.ILayoutElement;
 import spark.core.IViewport;
 import spark.core.ScrollUnit;
-import mx.events.PropertyChangeEvent;
-import mx.events.ResizeEvent;
 
 [IconFile("VScrollBar.png")]
 

     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    override public function step(increase:Boolean = true):void
    {
        if (!viewport)
            super.step(increase);
        else
            updateViewportVSP((increase) ? ScrollUnit.DOWN : ScrollUnit.UP);
    }
    
    /**
     *  @private

    override protected function sizeThumb(thumbSize:Number):void
    {
        thumb.height = thumbSize;
        thumb.visible = thumbSize < trackSize;
    }
    
    /**
