<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/10/19/toggling-the-drop-shadow-on-a-panel-container-in-flex/ -->
<mx:Application name="Panel_dropShadowEnabled_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">
    
    <mx:Script>
        <![CDATA[
            private function checkBox_change(evt:Event):void {
                panel.setStyle("dropShadowEnabled", checkBox.selected);
            }
        ]]>
    </mx:Script>

    <mx:ApplicationControlBar dock="true">
        <mx:CheckBox id="checkBox"
                label="dropShadowEnabled:"
                labelPlacement="left"
                selected="true"
                change="checkBox_change(event);" />
    </mx:ApplicationControlBar>

    <mx:Panel id="panel"
            title="Panel title"
            width="100%"
            height="100%"
            borderColor="haloSilver">
        <mx:Label text="Panel contents" />
    </mx:Panel>

</mx:Application>