Can't Customer a Customer Center Role

I tried to edit a customized customer center role, and ran into a strange problem.  So I started fresh and attempted to customize the standard Customer Center role, but ran into the same problem:  each option level of each transaction permission is on a separate line.  For instance, there are five different lines of 'Cash Sale', with one permission option each of 'view', 'create', 'edit', etc.  When I click on one of the line items, a pop-up error window says, 'Permission must be unique.' 

This is only happening with the Customer Center roles.  All the other roles are behaving OK.