What do you mean by "the case when focus is elsewhere"? The way this extensions works is whenever you press [Spacebar] key it will play/pause video on the page. The only case when it doesn't is when you type some text in search bar or comments section. I would be grateful for a more detailed explanation :)
You can write me on my mail: mrquackduckk@gmail.com Or just edit your current reply with "P.S" block
