FLEX MDI窗口开发实例

主程序代码：
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
    layout="vertical"
    xmlns:mdi="ext.containers.windows.mdi.*"
    width="100%"
    height="100%"
    creationComplete="initCollections();">
 <mx:Script>
  <![CDATA[
   import mx.events.MenuEvent;
   import mx.collections.XMLListCollection;
   import mx.controls.Alert;
   import mx.managers.PopUpManager;
   import mx.managers.SystemManager;
   import mx.containers.Panel;
   import ext.containers.windows.mdi.ChildWindow;
   import mx.events.FlexEvent;
   private var menuBarXML:XMLList=
    <>                 <menuitem label = "windows">                     <menuitem label ="create window" data="createWindow"/>                     <menuitem label ="close window" data="closeWindow"/>                     <menuitem label ="max window" data ="maxWindow"/>                     <menuitem label ="min window" data = "minWindow"/>                     <menuitem label ="min all windows" data ="minAllWindows"/>       &nb