Hello,
I tried some other windowmanagers, too. But then i have to find a solution for nearly the same problem just for another windowmanager. Because I found the most relevant informations for KDE, I chose the KDE-solution. Unfortunately I just found most of the solutions for KDE, but not all. ;-)
Then configure fvwm2 in a way that the user cannot start anything else (I hope that is possible).
This is the problem I meant. I also don't know jow to configure this for fvwm2 or any other lightweight windowmanager. If someone wants to give me a hint to increase my knowledge of some other windowmanager than KDE I would be happy of an alternative solution.
Do you really need a window manager at all? You could also start your application so that it fills the whole screen (using the -geometry X option). If your application exits, the session will terminate and you get back to the login screen.
I forgot, I tried this way too. But I need some of the supplies of an windowmanager for my program. For example when I want to open a sub-dialog of my program, I got a password dialog. When I run my program without windowmanager, it's not possible toenter the password into the LineEdit. It gets no focus. And I have no window decorations (just for some better look and clarity). Thank you nevertheless. Marc