By now you probably know that one of Firefox 3.5 main features is the ability to show video encoded in Theora format natively, that is without the need of a plugin or any other software.
As good as this is, it has no option for showing the video in full screen. But as usual, it didn’t take much time before a extension came to the rescue to provide the necessary feature (in fact it has been available before Firefox 3.5 final).
Full Screen Video, by Dao Gottwald adds an option to video’s context menu to view a video in full screen mode. Right-click, select and watch.
There are a couple of caveats though: the video restarts when switching to full screen but I found it to be a problem much less annoying than I thought it would be. Also, full screen is only achieved on Windows. On other platforms it’s just a maximized window.
And if you don’t like the native video controls or get bored of them, you can customize them as almost everything else, Firefox audio and video controls are customizable (more work for theme authors!).