MyBB Community Forums

How can I make a forum visible to a user when his primary groupd doesn't have access to the forum.
Per example:
A user has "registered" as his primary group and "auteur" as an extra group.
Now I have a forum called "Auteur's are".
Which i edited the permissions, to not show to the group "registered".
But now, it also doesn't show up for members with the extra group "auteur".
For which i set the permissions to view the forum.

Help!

This is most likely some sort of a bug: http://community.mybb.com/thread-158694.html You can bump that thread and state that you're experiencing this issue so it gets more attention.