ssh session does not close properly

[David Hopkins]

On my ltsp servers I found that ssh sessions started with

ssh -X server1 some_app

from a command line do not exit cleanly when some_app is closed.
Instead, the app's GUI interface closes but you do not get a prompt
back.  A CTRL-C returns the command line prompt.  This is using
Karmic.  Has anyone else observed this behavior and been able to
determine why it happens?

Thanks!
Dave Hopkins