Forum Help understanding "Edit Moderator (name) for forum (forum name)"
 

Ok, I assigned a moderator to a specific forum. I come to a page that says "Edit Moderator Fred for forum General Chat"

I understand all the forum-related settings, like Post/Thread Permissions, Forum Permissions, etc., as they seem to apply to a forum. But I'm confused about why the "Group" permissions, USer Permissions, etc are in this section? For example, if I set "Can Delete Groups" for this forum, can I set it to a different setting for the same moderator in a different forum? How can you have different "Groups Permissions" in different forums? It would seem a moderator could either delete / edit groups or he can't? Maybe I just don't understand the concept of groups?