     // Methods
     //
     //--------------------------------------------------------------------------
-
-    /**
-     *  Position the thumb button based on the specified thumb position,
-     *  relative to the current Y location of the track in the control.
+    
+    /**
+     *  Update the value property and, if viewport is non null, then set 
+     *  its verticalScrollPosition to <code>value</code>.
+     * 
+     *  @param value The new value of the <code>value</code> property. 
+     *  @see viewport
+     */
+    override protected function setValue(value:Number):void
+    {
+        super.setValue(value);
+        if (viewport)
+            viewport.verticalScrollPosition = value;
+    }
+        
+    /**
+     *  Position the thumb button according to the given thumbPos parameter,
+     *  relative to the current y location of the track in the scrollbar control.
      * 
      *  @param thumbPos A number representing the new position of the thumb
      *  button in the control.

        super.partAdded(partName, instance);
    }     

    
}


import mx.layout.ILayoutItem;
import mx.layout.LayoutItemFactory;
import mx.components.baseClasses.FxScrollBar;   
import mx.events.PropertyChangeEvent;
import mx.events.ResizeEvent;
import flash.events.Event;

/**
 *  The FxVScrollBar (vertical ScrollBar) control lets you control
