Add close handler to TitleWindow
<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Script> import mx.managers.PopUpManager import mx.containers.TitleWindow; import mx.controls.TextArea; import mx.events.CloseEvent; private var _window:TitleWindow; private function showWindow(event:Event):void { var textArea:TextArea = new TextArea( ); textArea.text = "this is a test"; textArea.height = 200; _window = TitleWindow(PopUpManager.createPopUp(this, TitleWindow)); _window.addChild(textArea); _window.showCloseButton = true; _window.addEventListener(CloseEvent.CLOSE, closeHandler); } private function closeHandler(event:CloseEvent):void { PopUpManager.removePopUp(_window); } </mx:Script> <mx:Button id="button" label="Show Window" click="showWindow(event)" /> </mx:Application>