It just opens the video in a separate tab. It does not display on top all the time. Opera GX has this feature built in if anyone wants to try.

簡單易懂的插件，very good！

It's great! I've been using it for so long, but... there's an anoying issue lately: the content in the popup window looks normal but actually they're about 50px below than they really are. I explain it: for example if you want to click over any element, you have to do it 50px below than what you are actually seeing. It also means that it's impossible to click over the video controls, since they're at the bottom of the window and there's no more space below to click, so you have to use the Tab key to navigate between video controls and options. It's been happening for a few months. I don't know if it's because of a browser update or a plugin update, but it was OK before that. I know it's not my SO or something because I just formatted and reinstalled everything and the issue is still there. By the way, using the last browser/plugin version, the "Point top left corner to open menu" tag never dissapears, but the little triangle hover link on the top left corner that shows the link to come back to youtube is also affected by that "backend alignment" problem. I hope you could fix this up and make this plugin entirelly awesome again!! Thanks for the good/hard work!!!

UPDATE: I'm so happy because with this last Firefox update (70.0) the position of the elements is correct now. So, it means that it was a browser problem (Maybe someone left a {} or () opened LOL). BUT, there's still one issue left: The top left tag that shows "Point top left corner to open menu", because it never dissapears, so you cannot clic over the link behind. I hope you could fix it soon and again, thanks a lot for this awesome add-on!

На самом деле просто открывает другое окно и там уже видео играет. Поверх всех окон не работает. Даже поверх всех вкладок браузера тоже.

You can add ALWAYS ON TOP FUNCTION WITH THIS ADD-ON "https://addons.mozilla.org/en-US/firefox/addon/always-on-top/" just use the Ctrl+Shift+F7 shortcut to activate it in the popup window created by this add-on. Now I have what I was searching for. This even works outside of Firefox.

It would also be awesome if Hooktube would be supported, or YouTube as a third party in general.

Bug Info: Sometimes the left corner menu doesn't work.

Thank you for your work and time spend.

exactly what i was looking for.

how to set always on top?

It's a bit confussing, but it works. To turn it on just right click in the web browser and you'll see the enable option.

I don't know how to tun it at all ?!
Screenshots and a user guide would be appreciated, otherwise everybody will give up using it...
I'm using Firefox 58.0.2 (64-bit) on Ubuntu.