      *  change the horizontal scroll position for page up or page down by 
      *  scrolling the viewport.
      *  This method calculates the amount to scroll by calling the 
-     *  <code>IViewport.horizontalScrollPositionDelta()</code> method 
+     *  <code>IViewport.getHorizontalScrollPositionDelta()</code> method 
      *  with either <code>flash.ui.Keyboard.PAGE_UP</code> 
      *  or <code>flash.ui.Keyboard.PAGE_DOWN</code>.
      *  It then calls the <code>setValue()</code> method to 

     *
     *  @private
     */
    private function updateViewportHSP(unit:uint):void
    {
        var delta:Number = viewport.horizontalScrollPositionDelta(unit);
        setValue(viewport.horizontalScrollPosition + delta);
    }
    

     *  @see mx.components.baseClasses.FxTrackBase#setValue()
     *  @see mx.core.IViewport
     *  @see mx.core.IViewport#horizontalScrollPosition
     *  @see mx.core.IViewport#getHorizontalScrollPositionDelta()
     */
    override public function step(increase:Boolean = true):void
    {
        if (!viewport)
            super.step(increase);
        else
            updateViewportHSP((increase) ? ScrollUnit.RIGHT : ScrollUnit.LEFT);
    }   
    
    /**
