Can't change login screen

I played around with the Login manager in the Control Center (SLES 7) and tried different login screen configurations. Now I'm stuck and can't change the login screen anymore. I go to the login manager (as root of course), and make changes to the settings. But after restarting the x-server and even rebooting the machine, the changes take no effect. What can I do about this? Christoph Ruepprich "There is nothing as deceptive as an obvious fact."--Sir Arthur Conan Doyle