Graphical User Interfaces

Dialogs

A mode restricts what a user can do at any given time, or interprets a user in a way that depends on the mode.
Example: In over type mode in a word processor, the typed characters replace existing characters instead of inserting themselves before the cursor.
Experience has shown that modes burden program users - the user must expend some mental effort and keep track of the current mode.
When designing a user interface, it is generally preferred to minimize modes.