arcgis for flex 中Panel拖动

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
????? xmlns:s="library://ns.adobe.com/flex/spark"
????? xmlns:esri="http://www.esri.com/2008/ags"
????? xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
???
?
?<fx:Declarations>
??<!-- 将非可视元素（例如服务、值对象）放在此处 -->
?</fx:Declarations>?
?<esri:Map crosshairVisible="true">
??<esri:ArcGISTiledMapServiceLayer
???url="http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" />
?</esri:Map>
?<s:Panel mouseDown="move_panel();" mouseUp="stop_panel();" id="ml" x="273" y="120" width="250" height="200" title=" 信息" >
??<s:Label id="lbinfo" x="3" y="5" text="提示信息"/>
?</s:Panel>
?
?<fx:Script>
??<![CDATA[
???public function move_panel():void{?
????
????ml.startDrag();?
????
???? }?
???
??????
???
??? public function stop_panel():void{?
????
????ml.stopDrag();?
????
???? }

??]]> ?</fx:Script> </s:Application>