Hi there!
Thank you for you answer.
It's really seams to be broken / mal-configured. I manually removed the
users from the allGroup for testing.
Both properties xwiki.users.initialGroups and
xwiki.authentication.group.allgroupimplicit are
commented / deactivated, but new users do land in the allGroup without
problem.
What worries me the most is that if the user has no group at all and no
permission at all it still can see and edit the wiki.
Don't see how that is going to help activating those properties since users
in no group should have no permission granted at all right? And users that
are not in the allGroup but inside an explicit group should have that
group's permission, but that is not the case...
Best regards,
OJ