Detach- Event on idle session not fired on missing heartbeats

Hi all,
I’m struggling with catching the detach events for idle sessions to clean some cache. I’m using V7.0.4
I followed the guidance in the BOV at
and the wiki at

The web.xml configuration parameters ‘heartbeatInterval’ and closeIdleSessions (true) are likely set correct:


which shows a request to the session parameters in the UI: getSession().getConfiguration().getHeartbeatInterval() (=20sec)/ isCloseIdleSessions() (=true).

I call my application in Firefox and follow the heartbeats with the httpFox- tracer add-on. Perfect !
I change the URL to ‘about:blank’ and the heartbeats vanish ! Perfect !

I wait 3 heatbeat intervalls and … nothing happens.

My app is as simple as can be:

public class SimpleiUI extends UI implements DetachListener{

	protected void init(VaadinRequest request) {

		final VerticalLayout layout = new VerticalLayout();

		System.out.println("UI-IdleTimeout: " + getSession().getConfiguration().getHeartbeatInterval() + ",IdleClean:"+ getSession().getConfiguration().isCloseIdleSessions() );

	public void detach(DetachEvent event) {
		System.out.println ("Detach listener");

I’m lost, where is my misunderstanding ?

Thanks for any help !