Which Event is invoked on clicking the Close button of AIR Window

Hello

I am trying to capture the event; which is invoked when we close the AIR window by clicking its Close button (on the top-right corner). I have tried the following; but none of them seems invoked:

newWin.stage.addEventListener(Event.CLOSING, closeHandler);
newWin.stage.addEventListener(Event.EXITING, closeHandler);
newWin.stage.addEventListener(Event.REMOVED, closeHandler);
newWin.stage.addEventListener(Event.DEACTIVATE, closeHandler);
newWin.stage.addEventListener(Event.REMOVED_FROM_STAGE, closeHandler);

The code for the said problem is something like the following:

var initOptions: NativeWindowInitOptions = new NativeWindowInitOptions();
initOptions.systemChrome = NativeWindowSystemChrome.STANDARD;
var newWin: NativeWindow = new NativeWindow(initOptions);;
newWin.stage.addEventListener(Event.CLOSING, closeHandler);

Would anybody kindly help!