My laptop recently died and I had to buy a new one. Since I ended up with an extra hard drive, I decided to use the space to install a KDE distro, as I’ve used Gnome pretty much exclusively. I ended up picking kubuntu 10.10 to try. The installation was smooth and polished as expected from Ubuntu, however, shortly after logging in, I was suddenly logged out and sent back to the KDE login screen.
This happened a few more times before I realized that X server was restarting. Some additional trial-and-error lead me to the problem: X server was restarting every time I pressed Shift + Backspace. I’ve head of CTRL + ALT + Backspace restarting X, but Shift + Backspace was new and all too easy to trigger by accident.
The fix is pretty easy though. Open your ~/.Xmodmap file and change this line:
keycode 22 = BackSpace Terminate_Server BackSpace Terminate_Server
keycode 22 = BackSpace BackSpace BackSpace BackSpace