@leocg Thank you, this worked.

@leocg I can turn the video to regular mode but when I watch a new video, it automatically enables it again. So I have to turn off theater mode EVERY time, and I just watch a lot of youtube.

So I don't know why but all of the sudden one day I just clicked on youtube and it automatically enabled Theater mode for youtube. It's been a few months and I still don't know how and why it's happening. I tried disabling all my extensions related to youtube and it still kept doing it. Chrome is working perfectly fine for me and doesn't have this problem so..