I have a lot of nested buttons in a vbox. How can I put a popuped titlewindow in the center position of the button clicked.

The codes is:

 <mx:Canvas width="100%" bottom="0">
  <mx:Canvas backgroundImage="@Embed('/assets/background/ButtonBar.png')"
       width="100%" y="15" height="30" horizontalCenter="0"/>
  <mx:HBox id="ButtonGroup" y="6" horizontalCenter="0">
   <mx:Button id="WorkAlertBtn" label="¹¤×÷ÌáÐÑ" click="workAlert_clickHandler(event)" width="95"/>
   <mx:Button id="IntergratedQueryBtn" label="×ۺϲéѯ" width="95"/>
   <mx:Button id="SummarizeBtn" label="×ۺϸſö" width="95"/>
   <mx:Button id="ThematicBtn" label="רÌâͼ" width="95"/>
   <mx:Button id="StatisticalAnalysisBtn" label="ͳ¼Æ·ÖÎö" width="95"/>
   <mx:Button id="DocumentBtn" label="µç×ÓÎĵµ" width="95"/>
   <mx:Button id="ChatBtn" label="½»Á÷ƽ̨" click="ChatBtn_clickHandler(event)" width="95"/>
  </mx:HBox>

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