It seems like a recent Compiz update has fixed this so I've marked this as invalid.
** Changed in: thunderbird (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/853092 Title: Thunderbird does not minimise properly To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/853092/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs