<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white" viewSourceURL="srcview/index.html">

    <mx:Script>
        <![CDATA[
            private function comboBox_change(value:String):void {
                myButton.label = value;
                myButton.setStyle("borderColor", value);
                myButton.setStyle("themeColor", value);
            }
        ]]>
    </mx:Script>

    <mx:ComboBox id="comboBox"
            prompt="Please select a color..."
            selectedIndex="-1"
            change="comboBox_change(event.currentTarget.selectedLabel)">
        <mx:dataProvider>
            <mx:Object label="haloBlue" />
            <mx:Object label="haloGreen" />
            <mx:Object label="haloOrange" />
            <mx:Object label="haloSilver" />
        </mx:dataProvider>
    </mx:ComboBox>

    <mx:Button id="myButton"
            emphasized="true"
            fontSize="16"
            width="{comboBox.width}"
            height="{int(comboBox.width * 0.5)}" />

</mx:Application>