I have a peculiar problem that only came about recently, though there were no recent changes made to Zimbra (current version 6.0.5)

Inside the admin console, for our COS (we use the default), the preference "Display a warning when users try to navigate away from ZCS" is enabled for the users as well as the administrators.

This did work in the past though now no one gets prompted with the log off warning. When I go to the Server Statistics / Sessions tab, I see several admin sessions (as well as a few duplicate user sessions), but they never seem to disappear. Myself and one other person have access to the admin console, so it is not as though users are getting in and mucking around with things.

Any ideas on why we don't get prompted when trying to navigate away from Zimbra?

Sir Bob