     //----------------------------------
 
     /**
-     *  @copy mx.layout.LayoutBase#horizontalScrollPositionDelta
-     */
-    public function verticalScrollPositionDelta(unit:uint):Number
+     *  @copy mx.layout.LayoutBase#getVerticalScrollPositionDelta
+     */
+    public function getVerticalScrollPositionDelta(unit:ScrollUnit):Number
     {
         // TBD: replace provisional implementation
         var scrollR:Rectangle = scrollRect;

            
        switch (unit)
        {
            case Keyboard.UP:
                return (scrollR.y <= 0) ? 0 : -1;
                
            case Keyboard.DOWN:
                return (scrollR.y >= maxDelta) ? 0 : 1;
                
            case Keyboard.PAGE_UP:
                return Math.max(minDelta, -scrollR.height);
                
            case Keyboard.PAGE_DOWN:
                return Math.min(maxDelta, scrollR.height);
                
            case Keyboard.HOME: 
                return minDelta;
                
            case Keyboard.END: 
                return maxDelta;
                
            default:


import mx.core.IViewport;
import mx.core.UIComponent;
import mx.core.ScrollUnit;
import mx.events.FlexEvent;
import mx.events.TextOperationEvent;
import mx.utils.TextUtil;
