*of course due to the wide screen nature of monitors they aren't actually infinite because you'll almost always have significant horizontal velocity by the time your pointer gets there causing you to have to stop and carefully move your mouse just as much as if you had window-attached menus and often further if you've rammed into the corner furthest from your desired menu. The RiscOS/NeXT approach of putting the menus in the context menu is arguably best for acquisition speed although probably worse for discoverability because you have to take an action before you can see even the top-level of the hierarchy.