[flexcoders] MoveEvents.MOVE for Popwindow doesn't work?

[flexawesome]

Hi guys,

I am reading the article here for popwindow 

http://livedocs.adobe.com/flex/201/html/wwhelp/wwhimpl/common/html/wwhelp.htm?context=LiveDocs_Book_Parts&file=layouts_065_45.html

I am going to addEventListenser for the popwindow, if the popwindow
moved, I need to update the label, it seems MoveEvent doesn't work for
popwindow, any idea?

THANKS A LOT

====================== MAIN XML ==========================

<?xml version="1.0"?>
<!-- containers\layouts\MainMyLoginForm.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml";>

    <mx:Script>
        <![CDATA[
            import mx.managers.PopUpManager;
            import mx.core.IFlexDisplayObject;
            import mx.events.MoveEvent;
            import flash.events.MouseEvent;
            
            import MyLoginForm;

            private function showLogin():void {
                // Create a non-modal TitleWindow container.
                var helpWindow:IFlexDisplayObject =
PopUpManager.createPopUp(this, MyLoginForm, false);
                
                helpWindow.addEventListener(MoveEvent.MOVE,updateText);
            }
            
            private function updateText():void{
                textLabel.text = "I am not a blank label! cool"
            }
        ]]>
    </mx:Script>
    
    <mx:VBox width="300" height="300">  
        <mx:Button click="showLogin();" label="Login"/>
    </mx:VBox>
    
    <mx:Text id="textLabel" text="I am a blank label now"/>
</mx:Application>

============================================================



================ component: MyLoginForm.mxml ===============
<?xml version="1.0"?>
<!-- containers\layouts\myComponents\MyLoginForm.mxml -->
<mx:TitleWindow xmlns:mx="http://www.adobe.com/2006/mxml";>
    
    <mx:Script>
        <![CDATA[
            import mx.managers.PopUpManager;
            
            private function processLogin():void {
                // Check credentials (not shown) then remove pop up.
                PopUpManager.removePopUp(this);
            }
        ]]>
    </mx:Script>

    <mx:Form>
        <mx:FormItem label="User Name">
            <mx:TextInput id="username" width="100%"/>
        </mx:FormItem> 
        <mx:FormItem label="Password">
            <mx:TextInput id="password" 
                displayAsPassword="true" 
                width="100%"/>
        </mx:FormItem> 
    </mx:Form>
    <mx:HBox> 
        <mx:Button click="processLogin();" label="OK"/> 
        <mx:Button 
            label="Cancel"
            click="PopUpManager.removePopUp(this);"/> 
    </mx:HBox> 
</mx:TitleWindow>
======================================================