Desktop gets stuck

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 in the sense that all applications remain alive and no user input is lost. The third, reboot, is the ultimate measure.

Harmless
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.

Harmless
If the above procedure does not work, use Ctrl-Alt-F2 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-F7 to re-enter the graphics mode. All applications remain alive.

Reboot
If the above procedures do not work, use Ctrl-Alt-F2 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.

2019-11-13