Watching a video while working

I do this sometimes (if it's a video you don't need to concentrate on, just glance at from time to time), but it can be awkward because you need to make both windows narrow, beside each other.

BUT I've just found a function in Firefox which allows you to pop the video out into it's own little window which you can place on top of everything else, and move around to wherever suits you.

That's handy!