<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/05/23/setting-the-background-color-and-background-alpha-for-a-numericstepper-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white" viewSourceURL="srcview/index.html">
    
    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="backgroundAlpha:">
                <mx:HSlider id="slider"
                        minimum="0.0"
                        maximum="1.0"
                        value="1.0"
                        snapInterval="0.1"
                        tickInterval="0.1"
                        liveDragging="true" />
            </mx:FormItem>
            <mx:FormItem label="backgroundColor:">
                <mx:ColorPicker id="colorPicker"
                        selectedColor="white" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>
    
    <mx:NumericStepper id="numericStepper"
            backgroundAlpha="{slider.value}"
            backgroundColor="{colorPicker.selectedColor}" />
    
</mx:Application>