I have a database where most users will be accessing as read only.

I want to have users login instead of using the guest login, and would also like to restrict the scripts and layouts they have access to.

I tried duplicating the Read Only privledge set and modifying it, but it seems if I change anything, the user can no longer modify global fields. If they login as a guest, they can access the global fields with no problem.

What am I missing?

I went in and set the global fields as modifyable, and it works now.

Well the real solution here is not to use either of the default subordinate Privilege Sets, but rather you should make your own custom Privilege Sets. The item you describe is a known issue.

Steven