Registered users vs. Members on the "Who can view?" column

[Planet Jackson]

1.  I have not invited or authorized anyone to become a member of my forum.  I have told individuals to register, which works fine for my forum.
2.  Under who can view the forum, there are only 2 options:  everyone and members.  When I try to click on members to make it private, the choices under "who can create new topics" and "who can reply" jumps from "registered users" to "members" automatically.  It is not possible to change this back to "registered users".  I don't want to go through the trouble of adding members to my site right now.  Why can't I choose "registered users"?
3.  These settings make it impossible to see the list of registered users for the site under the "people" tab.  When I change it back to "everyone" the avatars and demographics reappear.

Ideally, I would like to make my forum viewable only to registered users without having to add them as members and while maintaining the feature to see everyone else who has registered.  Would adding the "registered users" option to the "who can view" column solve this problem? Is this a glitch?  Will it be fixed soon?  

[Hugo <Nabble>]

Planet Jackson wrote

2.  Under who can view the forum, there are only 2 options:  everyone and members.  When I try to click on members to make it private, the choices under "who can create new topics" and "who can reply" jumps from "registered users" to "members" automatically.  It is not possible to change this back to "registered users".  I don't want to go through the trouble of adding members to my site right now.  Why can't I choose "registered users"?

Since only members can view the forum, how can a non-member be able to create a new topic or reply to a post? This doesn't make sense and we disable such options.

By reading your post, I assume you misunderstood the meaning of "registered user". For Nabble, a registered user is any user that has registered an email address on the Nabble website. This is not tied to a particular forum and has nothing to do with membership. So the People page can have at most three tabs: posters (any Nabble user who has left at least one message in the forum), members and administrators. If only members can view the forum, the posters tab doesn't make sense.