      */ 
     protected function system_mouseWheelHandler(event:MouseEvent):void
     {
-        var newValue:Number = nearestValidValue(value + event.delta * stepSize, stepSize);
-        setValue(newValue);
-        event.preventDefault();     
-    }
-    
-    /**
-     *  @private
-     *  Handles the mouseWheel event when the component is in focus. The thumb is 
-     *  moved by the amount of the mouse event delta multiplied by the stepSize.  
-     */ 
-    private function stage_mouseWheelHandler(event:MouseEvent):void
-    {
-        if (event.target != stage)
-            return;
-
-        system_mouseWheelHandler(event);
+        if (!event.isDefaultPrevented())
+        {
+            var newValue:Number = nearestValidValue(value + event.delta * stepSize, stepSize);
+            setValue(newValue);
+            event.preventDefault();
+        }
     }
 
     //---------------------------------

    private function system_mouseUpSomewhereHandler(event:Event):void
    {
        systemManager.getSandboxRoot().removeEventListener(MouseEvent.MOUSE_UP, 
                                                           system_mouseUpSomewhereHandler);
        systemManager.getSandboxRoot().removeEventListener(SandboxMouseEvent.MOUSE_UP_SOMEWHERE, 
                                                           system_mouseUpSomewhereHandler);
        

     *  the mouse down point in clickOffset.
     */
    protected function thumb_mouseDownHandler(event:MouseEvent):void
    {        
        systemManager.getSandboxRoot().addEventListener(MouseEvent.MOUSE_MOVE, 
            system_mouseMoveHandler, true);
        systemManager.getSandboxRoot().addEventListener(MouseEvent.MOUSE_UP, 
            system_mouseUpHandler, true);
        systemManager.getSandboxRoot().addEventListener(SandboxMouseEvent.MOUSE_UP_SOMEWHERE, 
            system_mouseUpHandler);
        
        clickOffset = thumb.globalToLocal(new Point(event.stageX, event.stageY));
        dispatchEvent(new TrackBaseEvent(TrackBaseEvent.THUMB_PRESS));
    }

    /**
