Description: the existing windows cannot be moved or closed. New windows
cannot be created. Or something else is badly wrong with the desktop.
Hitting the Windows key (between Ctrl-Left and Alt-Left) seems to be a cure.
If this is not the helpful, you have to try the following procedures.
The first two are harmless, not on Debian-10, in the sense that all applications remain alive and
no user input is lost. On Debian-10 you might getted logged-out. The third, reboot, is the ultimate measure.
- If the keyboard still accepts input, use Alt-F2 to open a command widget and
supply 'r <enter>'. This restarts the Gnome shell, the 'desktop'. All applications
remain alive; under Debian-10 this is not always the case.
- If the above procedure does not work, use Ctrl-Alt-F3 to open
a non-graphical terminal, login as beamline user and issue pkill -3 gnome-shell. This
restarts the Gnome shell (desktop). Use Ctrl-Alt-F2 to re-enter the graphics mode.
All applications remain alive; under Debian-10 this is not always the case.
- Reboot If the above procedures do not work, use Ctrl-Alt-F3 to open
a non-graphical terminal, login as beamline user and issue tango stop and sudo /sbin/shutdown -r now.
This reboots the PC. All applications are terminated. Edits may got lost.