One option, of course, is to click on the menu (i.e. Kickoff application launcher, or what in Windows parlance would be called the "start menu") and choose "Log out". This will restart the desktop session. But this is tiresome as it requires four mouse clicks, and one must re-aim the mouse each time. And if the window manager is confused, it may not even be possible.
On Debian/Gnome, in such cases I would have to find some way to get to a bash prompt and there type
/etc/init.d/gdm restart. On openSUSE 12.2 with KDE, there is no
gdm, of course - it uses
# zypper info kdm Loading repository data... Reading installed packages... Information for package kdm: Repository: openSUSE-12.2-Update Name: kdm Version: 4.8.5-2.10.1 Arch: x86_64 Vendor: openSUSE Installed: Yes Status: up-to-date Installed Size: 2.5 MiB Summary: KDE login and display manager Description: This package contains kdm, the login and session manager for KDE.
And of course:
# ps ax | grep kdm 1160 ? Ss 0:00 /usr/bin/kdm
However, in openSUSE there is no
# ls /etc/init.d/*kdm* ls: cannot access /etc/init.d/*kdm*: No such file or directory
So, how to restart the X session? The answer is to press the key combination CTRL-ALT-Backspace twice in succession. Historically speaking, pressing it once used to terminate the X session, but in openSUSE this has been changed to twice, presumably to make it even less likely that someone might press that combination of keys by accident.
Beware, terminating the X session in this way closes all running programs you started during that session (except those that have been explicitly detached of course).