I've been having this issue since I've gotten the new opera browser. If I see a youtube video on my timeline and want to full screen it, my screen goes blank for a second, I see the player go full screen but then the video disapears and I am stucking looking at my facebook timeline without the player inside of it. In order to go back I must hit the escape button which allows me to control facebook again.

Yandex seems to have implemented this already, you should as well! It would be nice to watch my videos in full screen on another monitor without having to resize it all manually.

It would be nice to be able to use my hangouts chats in my sidebar! It would save me an open tab and a lot of ram

I would love to see an implementation like Yandex Browser has. It's efficient and saves a lot of time when browsing sites in another language.