When i try to fullscreen youtube, there is a transparent border on the left and top of the window that will not go away normally. The only temporary fix I found was pressing win+d twice to get rid of it. This seems to be a reoccurring issue as this only happens on firefox and nothing else. This reddit post helped me. https://www.reddit.com/r/firefox/comments/13eguvp/please_help_transparent_video_border_when_in/ Please let me know how to fix this permanently. I have also tried firefox safe mode and that curiously didnt have borders but even when i went out of safe mode and disabled all my extensions and cleared my cache, it didnt work.