      */ 
     override protected function createChildren():void
     {
+        super.createChildren();
+        
+        // mask the ViewNavigator contentGroup
+        contentMask = new SpriteVisualElement();
+        contentGroup.mask = contentMask;
+        
+        // contentBackground shadow is layered above the contentGroup
         contentBackgroundGraphic = new contentBackgroundClass() as SpriteVisualElement;
         addChild(contentBackgroundGraphic);
-        
-        super.createChildren();
     }
     
     /**

        // the shading and highlight are drawn in FXG
        var contentEllipseSize:Number = contentCornerRadius * 2;
        var contentBackgroundAlpha:Number = getStyle("contentBackgroundAlpha");
        
        graphics.beginFill(getStyle("contentBackgroundColor"),
            contentBackgroundAlpha);
        graphics.drawRoundRect(contentBackgroundGraphic.getLayoutBoundsX(),
            contentBackgroundGraphic.getLayoutBoundsY(),
            contentBackgroundGraphic.getLayoutBoundsWidth(),
            contentBackgroundGraphic.getLayoutBoundsHeight(),
            contentEllipseSize,
            contentEllipseSize);
        graphics.endFill();
        
        contentBackgroundGraphic.alpha = contentBackgroundAlpha;
    }
}

            setElementSize(contentBackgroundGraphic, unscaledWidth, contentGroupHeight);
            setElementPosition(contentBackgroundGraphic, 0, actionBarHeight + gap);
        }
        
        setElementSize(contentMask, unscaledWidth, contentGroupHeight);
        setElementPosition(contentBackgroundGraphic, 0, actionBarHeight + gap);
    }
    
    /**
