When the only function it can possibly serve is as a couple of extra buttons, not even usable in menus or as a pointer anywhere, why does it need to be on screen? It's doubly annoying because I've mapped everything to the keyboard only so it's not even used at all, it just serves as a distraction that can't be moved off-screen because it changes to the resize cursor like it's still in windowed mode.

The developers have stated on the Steam forums that they are looking into adding such and option.