A long time ago, it became fashionable, even recommended, to disable menu items when they could not be used. Don't do this. Users see the disabled menu item that they want to click on, and are left entirely without a clue of what they are supposed to...

A reader wrote in to ask what kind of desks we're going to be using for the new office. The ergonomics experts always want you to have your feet flat on the floor. So you have to adjust your seat height first. Then, your arms are supposed to be...