This might be an enhancement request, but in before 3.8 staff could add to each others public lists, but now you can only add to your own public lists.
I should note that this is true for superlibrarians - at least they should be able to edit all public lists.
I think the behavior you want is added by bug 7805, maybe?
Looks like it probably will. *** This bug has been marked as a duplicate of bug 7805 ***