     {
         if (skin && viewport)
         {
+            viewport.clipContent = true;
             skin.addItemAt(viewport, 0);
             viewport.addEventListener(PropertyChangeEvent.PROPERTY_CHANGE, viewport_propertyChangeHandler);
         }

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

import mx.events.PropertyChangeEvent;
import mx.components.baseClasses.FxComponent;
import mx.core.ScrollPolicy;
import mx.core.ScrollUnit;
import mx.managers.IFocusManagerComponent;

    
