             return;*/
 
         var nSteps:uint = Math.abs(event.delta);
-        var scrollUnit:uint;
+        var navigationUnit:uint;
 
         // Scroll event.delta "steps".  If the VSB is up, scroll vertically,
         // if -only- the HSB is up then scroll horizontally.
          
         if (verticalScrollBar && verticalScrollBar.visible)
         {
-            scrollUnit = (event.delta < 0) ? ScrollUnit.DOWN : ScrollUnit.UP;
+            navigationUnit = (event.delta < 0) ? NavigationUnit.DOWN : NavigationUnit.UP;
             for(var vStep:int = 0; vStep < nSteps; vStep++)
             {
-                var vspDelta:Number = vp.getVerticalScrollPositionDelta(scrollUnit);
+                var vspDelta:Number = vp.getVerticalScrollPositionDelta(navigationUnit);
                 if (!isNaN(vspDelta))
                     vp.verticalScrollPosition += vspDelta;
             }

        }
        else if (horizontalScrollBar && horizontalScrollBar.visible)
        {
            scrollUnit = (event.delta < 0) ? ScrollUnit.LEFT : ScrollUnit.RIGHT;
            for(var hStep:int = 0; hStep < nSteps; hStep++)
            {
                var hspDelta:Number = vp.getHorizontalScrollPositionDelta(scrollUnit);
                if (!isNaN(hspDelta))
                    vp.horizontalScrollPosition += hspDelta;
            }

            switch (event.keyCode)
            {
                case Keyboard.UP:
                     vspDelta = vp.getVerticalScrollPositionDelta(NavigationUnit.UP);
                     break;
                case Keyboard.DOWN:
                     vspDelta = vp.getVerticalScrollPositionDelta(NavigationUnit.DOWN);
                     break;
                case Keyboard.PAGE_UP:
                     vspDelta = vp.getVerticalScrollPositionDelta(NavigationUnit.PAGE_UP);
                     break;
                case Keyboard.PAGE_DOWN:
                     vspDelta = vp.getVerticalScrollPositionDelta(NavigationUnit.PAGE_DOWN);
                     break;
                case Keyboard.HOME:
                     vspDelta = vp.getVerticalScrollPositionDelta(NavigationUnit.HOME);
                     break;
                case Keyboard.END:
                     vspDelta = vp.getVerticalScrollPositionDelta(NavigationUnit.END);
                     break;
            }
            if (!isNaN(vspDelta))
