Hi Michael

Apologies for replying for the wrong product.

I think that the forum editing is controlled through the Group settings.

There is a Group content setting where you can choose Who can Create and edit content - the choice is Group administrators, all group members,, everyone except standard members.

You can see the members and member types in the Members tab of the group.

If you select the forums tab >Settings there is a setting for who can create topics and also who are the moderators for the group

See forum settings for more details 

Regards