When clicking the "Remember me on this computer" during login, after some time the user is logged out.
I'm using Active Directory as Security Realm.
I logged in at 09:19 and checked the "Remember me on this computer" checkbox.
At 10:10 I freshly opened the jenkins front page again and I was logged it.
At 11:38 again, and I found myself logged out.
All tests were conducted with Firefox 4, accepting cookies and such.
This is reproducible on an installation via Debian package. At the time of writing the version number is 1.405