A day or two ago, I was watching a YouTube video in Firefox. I hit the full screen button on the YT player and the player entered full screen mode. My browser asked me if I would like to allow YT to enter full screen mode, I clicked allow. Ever since, whenever I click the full screen button on any YT player/video, nothing happens. I do not have this issue in Chrome, I've tried clearing my online and offline cache, and I don't seem to have this issue with other video players in Firefox. Any help would be great. Thanks.