I just saw this thread, because I was searching for a solution for exactly the same problem with my Galaxy Note Pro.
When I saw that you also have the issue that the settings dialog switches to the Google search option, I wondered if Google search had something to do with this behavior.
So I deactivated the app "google search" in the application manager.
After that I finally was able to set up a restricted user and allow this user to use certain apps.
So I thought I should share this finding...
I haven't tried yet, but i think, after setting up the restricted user completely, google search might be reactivated again.
As I don't use the app google search very often, I am not quite sure about the consequences of deactivating and reactivating this app. But I think in worst case some settings may be reset to defaults.