Designed for Use, 2nd Edition

Modes Are Not Always Bad

Because of the problems they can cause, it’s no surprise that modes have a pretty bad reputation. In reality, that reputation is largely undeserved. Trying to make a user interface entirely nonmodal increases its complexity. Modes can be used to show functionality only when it is wanted; nonmodal interfaces are forced to offer a much wider array of possible user actions at any given time.

Modes are bad only when they are nonobvious, unexpected, or hard to leave. If the user intentionally changes a user interface’s mode, that mode is entirely obvious to her as long as it remains active, and she always knows how to leave that mode, then there is nothing wrong with using modes.

Keep these basic rules in mind, and your modes ...