EchoEvent with GenericForwardComposer

<window id="echoEventWin" title="Test echoEvent"
      apply="webui.test.EchoEventTester">
    
    <button id="btn_echo" label="Press me">
    </button>
</window>

public class EchoEventTester extends GenericForwardComposer {

	private static final long serialVersionUID = -1L;
	private Button btn_echo;

	private Window echoEventWin;

	public void onClick$btn_echo(Event event) {
		Clients.showBusy("Processing ...", true);
		Events.echoEvent("onLater", self, null);
	}

	public void OnLater$echoEventWin(Event event) {
		try {
			Thread.sleep(2000);
			new Label("Done.").setParent(echoEventWin);
		} catch (Exception ex) {
			// Log exception ..
		} finally {
			Clients.showBusy(null, false);

		}
	}
}