Flex Gumbo中如何通过trackingLeft和trackingRight样式，调整TextBox内容左右间距

<?xml version="1.0" encoding="utf-8"?>

<Application name="TextBox_trackingLeft_test"

xmlns="http://ns.adobe.com/mxml/2009"

layout="vertical"

verticalAlign="middle"

backgroundColor="white">



<ApplicationControlBar dock="true">

<Form styleName="plain">

<FormItem label="trackingLeft:">

<HSlider id="slider1"

minimum="0"

maximum="20"

value="0"

snapInterval="1"

tickInterval="1"

liveDragging="true" />

</FormItem>

<FormItem label="trackingRight:">

<HSlider id="slider2"

minimum="0"

maximum="20"

value="0"

snapInterval="1"

tickInterval="1"

liveDragging="true" />

</FormItem>

</Form>

</ApplicationControlBar>



<Box backgroundColor="haloSilver" backgroundAlpha="0.4">

<Graphic>

<TextBox id="textBox"

text="The quick brown fox jumps over the lazy dog."

trackingLeft="{slider1.value}"

trackingRight="{slider2.value}"

textAlign="justify"

textJustify="interWord"

fontSize="16"

width="400" />

</Graphic>

</Box>



</Application>