KDE User management

Hi,
i wonder if you can modify KDE so that users can only log in once with one session.
Currently, with KDE 4.5, i have the problem that user can log in several times and then ending up with an application used in a different session which means that you can not use it in the other session.
This happens mostly by accident.

man limits.conf

A quick goggle also gives the same data:

Linux Administrator’s Security Guide - Linux Limiting and Monitoring Users

Lews Therin

It does work, but i noticed if i use ‘@users hard maxlogins 1’ via PAM, that once the user logs out of the system and wants to login again, it is not possible.
Have to figure out if thats a bug or if the logout will not be counted. By logic the user is not present anymore, or the system counts 1 user login for the whole time the system is running.

Thanks already for the link. It did help.