On Fri, Jan 22, 2016 at 1:28 AM, Bogdan Sinitsyn <bogdan.sinitsyn@gmail.com> wrote:

Windows usually request full-screen by setting _NET_WM_STATE_FULLSCREEN, don't
they?

Some programs (notably Firefox) check _NET_SUPPORTED and use the old way (just open a fixed size window, size obtained from the size of the Xinerama screen, or from the root window if there isn't Xinerama info); we do not put _NET_WM_STATE_FULLSCREEN in _NET_SUPPORTED because it's an optional component that needs to be added to handleEventHook and layoutHook, and neither can be introspected to see if it should be advertised or not.