User search does 20 identical requests to the user directory

When doing a user search to add users to groups or add a user to an ACL, the same search is passed 20 times to the backend.
This is due to UserManagerImpl.getSuggestedEntries being called every time because select_users_results.xhtml calls principalListManager.suggestedEntries 4 times and this is done for every phase, and nothing is cached.