While the personal mirror is disabled, most settings and submenus can't be accessed. Many of these still make sense to allow editing even if the mirror is disabled since they don't need realtime feedback.

Of these, locking Masking is the most detrimental to ux. If you've joined a large instance and forgot to disable the Remote Users in your mirror, you have no choice but to risk tanking your fps to adjust the setting. (Take out mirror, navigate to masking, THEN disable remote users) If we could edit masking without taking out the mirror, life would be better.