Both monitors on my desk have a single button on the back side of the bottom right corner. The button can be pressed or pushed in each of the four cardinal directions (left, up, right, bottom). It's actually really nice. Since it's only one physical button, there's never any guessing which button you're on. And once you know the menu structure, common tasks can be done completely blind. (For example, I know that switching between input sources is press-left-press. I can do that without even looking at the screen.)