Keyboard applet freezes the system

The file /etc/default/keyboard is attached. As you can see, it permits two
keyboard arrangements: gb (English UK) and epo (Esperanto). It also sets the
right Win key to toggle between the two layouts.

The bar at the bottom of the screen shows an applet on the RHS which looks like
a keyboard and either the letters `en' or the letters `eo'. When I tried to
change from one layout to the other, the system froze. Only the mouse was
working. Attempts to end the session with Ctrl-Alt-BkSpace failed. Similarly,
Ctrl-Alt-Del also failed. I had to do a h/w reset.

This is definitely unsatisfactory.