I can confirm this behavior, the only way to get thunderbird back is to kill it and restart the app. If you try to click the launcher icon, it flashes for a bit then stop, but thunderbird does not come up.
$ apt-cache policy thunderbird thunderbird: Installed: 3.1.9+nobinonly-0ubuntu4 Candidate: 3.1.9+nobinonly-0ubuntu4 Version table: *** 3.1.9+nobinonly-0ubuntu4 0 500 http://us.archive.ubuntu.com/ubuntu/ natty/main amd64 Packages 100 /var/lib/dpkg/status ** Changed in: thunderbird (Ubuntu) Importance: Undecided => Medium ** Changed in: thunderbird (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/769327 Title: Unity does not show thunderbird as running... -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs