Blank Users (Users and Devices mode)

I was using the beta 1 version in users and devices mode, just upgraded to beta 3 and now I cannot add/change/view any users.

The users option is there, but when clicked, I just get a blank frame, with no way to add, modify or delete any users or any existing users listed.
Users were setup previously and are still listed if I go to the devices tab and set a default user for a specific device.

Is anyone using users and device mode?
Is this mode still supported?
Can I just change back to extensions mode with no ill effects?