Four years later, this is still a relevant request.
it would make working in Renoise a lot nicer in OSX, where you rely on control-left/right to navigate through full screen applications. That is currently “broken” because full screen isn’t actually full screen (of course it’s not technically broken, but it breaks user expectation by running counter to OSX conventions), as also makes it impossible to do normal thinks like running a program from the dock, or even just checking what time it is without having to minimize Renoise so it doesn’t interfere with normal desktop use.
I’d very much like to +1 the request to make Renoise use true full screen on OSX (using enterFullScreenMode or the like)