How often do you get inside an elevator and accidentally select the wrong floor, then have to endure angry glares from inconvenienced riders when you select another floor? Or how about the kid that lights up all the elevator buttons? All that's needed is an undo function--if you press a wrong button, then simply press it again to cancel the selection.

Elevator manufacturers need to implement this simple solution for a problem that has existed ever since the first elevator was installed, and which likely occurs thousands of times each day around the world!