If using Risk/Issue management, check to see if CA has yet fixed the bug in the "Assigned To" field. Without the Global-Resource-View All right, the list is blank, even with view rights granted via OBS.
We ended up customizing the lookup, removing the security rights - user can now assign a risk or issue to any active user, without gaining access to view everything about those users.
Yes - customized, not configured. We must remove this before each upgrade/patch install and put it back in afterwards.
Here's the problem: https://communities.ca.com/thread/241697491
Here's the idea: https://communities.ca.com/ideas/235716584
Problem was originally raised on 12.1 - we finally gave up waiting on CA to fix this and customized the lookup.
Still on 14.2. Planning to go to 15.1 2017Q1 - will see if the problem has been resolved, there, or not.