how to catch onclose event from a modal window

	<system-config>
		<disable-event-thread>false</disable-event-thread>
	</system-config>

<window title="win" border="normal" width="200px" height="200px" closable="true">
	<attribute name="onClose"><![CDATA[
		if(Messagebox.show("Are you sure to close the window?", "Question",
			Messagebox.OK | Messagebox.CANCEL, Messagebox.QUESTION) != Messagebox.OK){
			event.stopPropagation();
		}
	]]></attribute>
</window>

	/**
	 * If we close the dialog window. <br>
	 * 
	 * @param event
	 * @throws Exception
	 */
	public void onClose$window_GuestBookDialog(Event event) throws Exception {
		doClose();
	}


	/**
	 * Closes the dialog window. <br>
	 * <br>
	 * Before closing we check if there are unsaved changes in <br>
	 * the components and ask the user if saving the modifications. <br>
	 * 
	 */
	private void doClose() throws Exception {

		if (isDataChanged()) {

			// Show a confirm box
			final String msg = Labels.getLabel("message_Data_Modified_Save_Data_YesNo");
			final String title = Labels.getLabel("message.Information");

			MultiLineMessageBox.doSetTemplate();
			if (MultiLineMessageBox.show(msg, title, MultiLineMessageBox.YES | MultiLineMessageBox.NO,
					Messagebox.QUESTION, true, new EventListener() {
						@Override
						public void onEvent(Event evt) {
							switch (((Integer) evt.getData()).intValue()) {
							case MultiLineMessageBox.YES:
								try {
									doSave();
								} catch (final InterruptedException e) {
									throw new RuntimeException(e);
								}
							case MultiLineMessageBox.NO:
								break; //
							}
						}
					}

			) == MultiLineMessageBox.YES) {
			}
		}

		this.window_GuestBookDialog.onClose();
	}

     myWindow.addEventListener("onClose", new EventListener() {
	
	@Override
	public void onEvent(Event event) throws Exception {
		// TODO Auto-generated method stub
		
	}
});