plasmashell hangs, making launcher, and all related stuff stuck. in some cases
it even seems to kill the wireless connection.
if it happens when resuming and screenlock is configured, the login (kdm, ssdm)
is not accepting mouse or keyboard input.


hovering over etc also show no response.
applications (browser etc) keep functioning normally
switching between applications has to be done with alt-tab, since the launcher
does not work.

it happens randomly as far as I can tell: while actively using the desktop,
when logging on again, with or without having been suspended. 

work around is:
alt-tab to start krunner (or when the screenlock login is active, open a
console )

then set DISPLAY to :0 if on a console
then do:
$ killall plasmashell
# wait for plasmashell to terminate
$ plasmashelll

everything works again.
extremely annoying, especially when in the middle of a presentation or so.....