There is a BUG in User Accout.
I made another account: User.
I checked "Playback control" but it does not remain checked, even if the function works: User can use "Playback control".
I made some tests.
When I switch from Admin to another User "Playback control" is unchecked by default
. That is a real BUG
User must have control over playback, don't you think? He is in LIVE and he must Play, Stop, Next etc., etc.
Great ideea with blank password
So, I created a general User with blank password.