Hi,
>
> When I lost internet connection and rdesktop was in fullscreen mode I
> wasn't able to close the rdesktop window (CTRL+ALT+ENTER didn't
> help). Then I tried to switch to other linux windows using ALT+TAB
> hoping that I can leave rdesktop and close it later. I was able to
> select the desired window during switching but I was switched back to
> rdesktop window which as I said was in fullscreen mode. So I saw no
> other way than to restart the PC.
>
That is a known issue with rdesktop due to how it is internall designed.
We have an issue #17 [1] for this bug. You could try compile rdesktop
from source to get commit 2a6298a which implements WM_PING. WM_PING is
used by the WM (Window Manager) to check if an application is alive and
usally present a dialog to give a choice to wait or terminate the hung
application.
[1]
https://github.com/rdesktop/rdesktop/issues/17
Kind Regards,
Henrik Andersson