Hi,
This has been noted as a bug as I understand.
Turn off class in top plan view and you can’t touch it, Rotate to 3d (hit 1 on keyboard) and you can’t see it, go back to top plan view and it’s still on.
To turn it off - With the class on in top plan view rotate to 3d and turn class off, rotate back to top lane and its off.
Strange behaviour.