ctrl+alt+backspace = frozen term screen

[john]

Hi all,

When I was using ltsp 4.2/ubuntu 6.10 last year if I student locked
their screen and left, the teacher could kill the xsession by doing
ctrl+alt+backspace and get the greeter again. This year, using
Edubuntu 7.04 that action results in a frozen black screen with some
complaints on it. Is there a new way to kill the xsession that teacher
can use or do we have to restart the thin client?

Thanks!

John