You should use 'kdesu' to run X programs with root privileges. If you really don't like that, you should allow local connections to the X server.
$ xhost local: -- Kate throws a screen of errors when invoked using sudo... kate still starts https://launchpad.net/bugs/64735 -- kubuntu-bugs mailing list kubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs