Hello! I'm having an issue specifically in Firefox Developer Edition only. Whenever I set a video to go fullscreen from any domain/service, little strips on the top of left of the fullscreen video show my desktop (shown in attached screenshot). I've tested this in regular Firefox as well as Google Chrome and fullscreen videos work just fine on both of those browsers. Before this current version update, this problem would happen the first time putting a video in fullscreen, but every subsequent attempt during the same browser session would not have the issue. However, I'm now unable to achieve a true fullscreen video in Firefox Developer Edition no matter how many times I try. Currently on version 145.0b3 (64-bit)