Did not find it useful after using it for over a week. A few times it got accidentally clicked, but the most annoying thing that made me remove this, is the fact you cant scroll after you enable this mode. So I would suggest you update this, and I'll try it again, and consider changing review.

BUG: when active + hit BACK = no scrollbar

Simple and effective

Works perfect save for one thing, the hotkey registers even when writing a comment on YouTube. Every single time I use the letter W it throws it in/out of full window mode. Any chance of sorting that? Other YouTube hotkeys don't trigger outside the video (such as space bar not unpausing and pausing it when hit, when writing up a comment)

Almost perfect but it would be great if you could enable scrolling down when enabled. Currently you have to deactivate it before you can scroll down. That and persistent mode; even if I shrink a window on one tab, if I open a video in a new tab, it should be fully windowed

Works perfectly well, except for one thing: you should unfocus your button once clicked in order to make that pressing space pause/unpause the video instead of enable/disable the windowed fullscreen feature. If you fix that, I give you the 5th star.

Edit : thanks. If you could fix that for other youtube buttons (fullscreen, mute/unmute, etc) even if I know it's not caused by your mod.

Superb. Lacks hotkey.

As mentioned in a previous review, if the video is pillarboxed (rather than letterboxed) the youtube masthead cuts of the top of the video.
This doesn't tend to be such an issue in a resizable window but is always the case in a maximized tab on a 16:9 screen which is the way I tend to use this.

It would also be nice if the progress bar and controls scaled with the window, although that is not a deal breaker like the above.

This is what I was looking for. Amazing work! you can fullscreen without worrying about double clicking to check another TAB ♥

Sorry to raid on the five star parade, but I am fully willing to change this review to 5 if this problem gets solved:

It cuts the top part of the video off, I assume because it wants to fill width and disregards available height.

Great addon! Just a small nitpick, would it be possible to add an option to make videos always start not maximized?