 import mx.core.IVisualElement;
 import mx.core.IVisualElementContainer;
 import mx.core.ScrollPolicy;
-import spark.core.ScrollUnit;
+import spark.core.NavigationUnit;
 import mx.events.PropertyChangeEvent;
 import mx.managers.IFocusManagerComponent;
 import flash.display.InteractiveObject;

            return;*/

        var nSteps:uint = Math.abs(event.delta);
        var scrollUnit: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;
            for(var vStep:int = 0; vStep < nSteps; vStep++)
            {
                var vspDelta:Number = vp.getVerticalScrollPositionDelta(scrollUnit);
                if (!isNaN(vspDelta))
                    vp.verticalScrollPosition += vspDelta;
            }

            switch (event.keyCode)
            {
                case Keyboard.LEFT:
                    hspDelta = vp.getHorizontalScrollPositionDelta(NavigationUnit.LEFT);
                    break;
                case Keyboard.RIGHT:
                    hspDelta = vp.getHorizontalScrollPositionDelta(NavigationUnit.RIGHT);
                    break;
                case Keyboard.HOME:
                    hspDelta = vp.getHorizontalScrollPositionDelta(NavigationUnit.HOME);
                    break;
                case Keyboard.END:                
                    hspDelta = vp.getHorizontalScrollPositionDelta(NavigationUnit.END);
                    break;
                // If there's no vertical scrollbar, then map page up/down to
                // page left,right
                case Keyboard.PAGE_UP:
                     if (!verticalScrollBar || !(verticalScrollBar.visible))   
                         hspDelta = vp.getHorizontalScrollPositionDelta(NavigationUnit.PAGE_LEFT);
                     break;
                case Keyboard.PAGE_DOWN:
                     if (!verticalScrollBar || !(verticalScrollBar.visible))   
                         hspDelta = vp.getHorizontalScrollPositionDelta(NavigationUnit.PAGE_RIGHT);
                     break;
            }
            if (!isNaN(hspDelta))
