Designed for Use, 2nd Edition

Unexpected Modes

Dialog boxes are a specific type of mode. Unlike nonobvious modes, dialog boxes are usually reasonably obvious, at least when they first pop up. They are, however, often unexpected, therefore causing the same problems as nonobvious modes: the user interface doesn’t do what the user wants because it is not in the mode the user expects.

Not only do dialog boxes change the mode of the user interface unexpectedly, but it’s also possible that the user’s input is mistakenly interpreted as input for the modal dialog box, rather than for the previously active window. (This is called stealing focus, since it moves the computer’s focus from ...