Rated 5 out of 5 stars
This is very useful for zombie mode. Why not override Firefox settings for full screen and allow the autohide of the Menu bar, Addon bar, and Windows Taskbar? That would make an awesome replacement for the Autohide extension that the other developer apparently gave up on.
Update: Yvard is absolutely right, this addon works wonderfully with Autohide by restoring the floating toolbars in full screen that were broken in Firefox 18. It additionally adds zombie mode while maximized without having to change any settings in Autohide so we get the best of both worlds at the same time. I just had to make sure "browser.fullscreen.autohide" in about:config was set to true. Well done.