BuzzPCSOS I am logged in, after I delete the YT cookies, I restart FF & it is Default for a sec then pops out to theater. I downloaded another browser (Brave) not stuck in Theater n Brave & a new FF profile fixes it, just odd IMO. Np idea why it even started, the button changes when Iclick it, but that is all. Synced with account, still good & Default is still Default.
Computers, you just love them right, this makes no sense.