This is really more of a feature request but I couldn't find anywhere but the old forums to post it and they hadn't been updated since 2010, I saw.

My idea would be really cool, I think. As I say in the title, a "window-ed full screen" is what I would like. I have no clue how you would go about this but I would really like to be able to tell Firefox, in a smaller window, to enter full screen and the URL bar, the favorites bar, everything disappears and all that's left is the web page. This way, users could maximise on window space and have, say, six windows that are each in this modified full screen open while writing a paper so they can view paper requirements, view a source, edit their references, etc. while still editing the main document with that window maximised. I have added a a screen shot below that demonstrates and explains a bit further what I would like to see implemented.