<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/04/20/setting-the-horizontal-spacing-between-items-in-a-linkbar-control-in-flex/ -->
<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 init():void {
                slider.value = linkBar.getStyle("horizontalGap");
            }
        ]]>
    </mx:Script>

    <mx:Array id="arr">
        <mx:Object label="Alert" />
        <mx:Object label="Button" />
        <mx:Object label="ButtonBar" />
        <mx:Object label="CheckBox" />
        <mx:Object label="ColorPicker" />
        <mx:Object label="ComboBox" />
    </mx:Array>

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="horizontalGap:" direction="horizontal">
                <mx:HSlider id="slider"
                        minimum="0"
                        maximum="20"
                        snapInterval="1"
                        tickInterval="1"
                        liveDragging="true" />
                <mx:Label text="{slider.value}" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:LinkBar id="linkBar"
            dataProvider="{arr}"
            horizontalGap="{slider.value}"
            initialize="init();" />

</mx:Application>