Layering over background image

[trevorh]

For the life of me I can't figure this out. I skinned a WindowedApplication 
with a background image. Added a group of buttons, however I can't seem to get 
them to layer properly over the background image of the WindowedApplication 
component. 


image in the skin
        <s:BitmapImage width="100%" height="100%" 
source="assets/randomBkgd.png" />


<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"; 
                                           
xmlns:s="library://ns.adobe.com/flex/spark" 
                                           
xmlns:mx="library://ns.adobe.com/flex/mx"
                                           skinClass="utilities.CustomAppSkin">
        
        <s:layout>
                <s:BasicLayout />
        </s:layout>
        
        <s:Group x="10" y="10" width="400" height="25">
                <s:layout>
                        <s:HorizontalLayout />
                </s:layout>
                
                <s:Button label="Button1" width="100" height="25" />
                <s:Button label="Button2" width="100" height="25" />
                <s:Button label="Button3" width="100" height="25" />
                
        </s:Group>


        
</s:WindowedApplication>