In the very first version of firefox with full screen mode it ended up doing just that, rendering full screen inside a normal window area in my tiling WM. It wa

In the very first version of firefox with full screen mode it ended up doing just that, rendering full screen inside a normal window area in my tiling WM. It was likely a bug/unimplemented feature at that stage, but to be honest it would have been nice to have as an option prior to pip.