Full screen maximize button in Mac OS
I seem to recall in OS 7, 8, and 9 that in the upper right hand corner there was a "full-screen" button (at least in some windows). I recall the square with two horizontal lines would minimize a window to just it's title bar (on - off action). I believe the square within a square would enlarge and reduce the size of the window (from current to maximum back to current). Perhaps maximum isn't the same as full-screen.
For example, look at the two square buttons in the upper right corner of the attached screen shot with a window.