Comment 23 for bug 772063

Encountered in 12.04 too. With gnome terminal. I also did 2 observations:

1) After I "unlocked" the application launcher, then run terminal from "dash", it didn't appear in the application bar at all, although the terminal was newly run. Also Alt+Tab didn't show it.

2) The second observation is more interesting. After I switched to another application windows, then switched to "Show desktop" to hide all applications, the terminal disappeared (without icon in the launch bar there is no way how to access it), but even listing processes (Ctrl+F1, login, then running "ps xf | grep term") didn't show anything, thus the terminal process was killed by someone!

After logout/login I couldn't reproduce it again...