Then I deleted this "private" Forum because I did not want to have this Forum anymore.
Then about one week later, I created about 30 new forums.
And one out of those 30 new Forums inherited the permission-settings which I have set for a Forum which was actually deleted about a week ago.
So even I deleted that one specific "private" Forum, the "permission settings" were somehow still in the system. I assume the Node-ID-number was saving those settings but those settings were not deleted when I deleted those specific forum.
So the new Forum-Node took over old permission-settings of a Forum-Node which did not exist anymore.
Do you get what I am trying to say ?