Previous to KDE 3.3 one would simply be able to do a sudo command to run another X app as a different user under KDE. Since I've installed 3.4.2 the other application does not have the right to access the display.
I'm guessing this have something to do with the upgrade to the complete new KDE package, but perhaps not.
Furthermore, doing a "xhost +localhost" does not solve the problem, I am required to do a "xhost +" before it works. This is of course a major inconvenience to running applications as another user.
BTW, anybod know why KDE does not support SUDOing natively rather than just SU'ing...? I hate typing passwords in all the time...