main-window closelistener not working with don't push ozonelayer?

Vaadin 6.8.12
Jetty 8
Different browsers
Don’t push ozonelayer 1.0.4

i’m developing a group-chat application.
There are basically two needs:

  1. keep track of logged in users
  2. make messages appear in “realtime”

The part about messages is already working without any problems.
But tracking logged-in users is quiet impossible because main-window close-listeners don’t seem to work as long as “don’t push” is working. They will neither get fired when i refresh the browsertab nor when i close the whole tab.

Sub-window close-listeners are working. (All tested Browsers)

I tried different Browsers and i could only get a single “windowclosed” message when switching from IE10 to IE8 using developer-tools.

Can anyone confirm this bug? Or provide any solution?

Thanks a lot!