Modify User screen - please explain User Group choices

[coppermine_user]

Ok, i completely understand the concept of users, groups and how they apply in coppermine.  No problems there.  My only confusion comes from the Modify User screen. 

In this screen,  there is a block labeled USER GROUP.  In this block, there is a drop down box, with a list of all the possible groups that the user can be in.  However, below the dropdown box is list of checkboxes.  These checkboxes ALSO include all the possible groups that the user can be in...

So, why is there a drop down box?  Is this the user's Primary Group or something along those lines?  If so, what does this primary group mean that the checkboxes don't?
If I choose the group "Family" from the drop down box, does that make the checkbox labeled "Family" meaningless?

Ok, that's it, i'm sure someone will clear this up quicky.  I would suggest adding a bit of comment about this in the documentation, I couldn't find any at all.  Thanks, I love Coppermine!  It has really saved me time over the past few weeks after a vacation with 3000+ pictures.

Jason

[coppermine_user]

Nobody?

[kegobeer]

The drop down box populates the user_group field, and the choices populate the user_group_list (in the _users table).  I imagine the user_group_list is for the ability to view group specific albums, etc, but I haven't done much with that.

[Tranz]

The primary group is associated with the user in the user's profile and memberlist.

[coppermine_user]

So, if I choose the FAMILY as someone's primary group, they are automatically allowed to see those galleries which I have allowed the group FAMILY to see.....

- or said another way -

If FAMILY is selected as the user's primary group in the dropdown, then the checkbox for FAMILY is pointless....

Are both of those statements correct?

thanks,
Jason