I just had a user change their display name. I did not think the had this ability. It's not happened before and I could see it might cause problems.
I can't find the setting to remove this permission. Can you help?
All users can change their profile information in My Profile > Accounts tab. I'm sorry, but you cannot restrict users to manage their own profile fields and accessing to their profile tabs.
However, there is an addon called user Custom Fields, which allows you to manage permissions of each field in each profile tab. Here is the addon page: https://gvectors.com/product/wpforo-user-custom-fields/ , just scroll down and read the description. Or read the documentation of that addon: https://wpforo.com/docs/root/addons/wpforo-user-custom-fields/