Alan Cooper

to minimize mouse movement

A dialog should have a title that clearly identifies its purpose. If the dialog is a function dialog, the title bar should contain the function’s action—the verb, if you will.

Use object names in property dialog title bars.

Modal dialogs are by far the more common variety. After a modal dialog opens, the owner application cannot continue until the dialog is closed. It stops all proceedings in their tracks. Clicking any other window belonging to the application only gets the user a rude beep for his trouble. All the controls and objects on the surface of the owner application are deactivated for the duration of the modal dialog.

Modeless dialogs are less common than their modal siblings. When a modeless dialog opens, the parent application continues without interruption. It does not stop the proceedings, and the application does not freeze. The various facilities and controls, menus, and toolbars of the main window remain active and functional.

First, modal dialogs must include one or more terminating commands, usually in the form of large pushbuttons at the bottom of the dialog.

Second, modeless dialogs should not use terminating command buttons. Instead, they should use the Close control in its window title bar.

Third, modal dialogs should not use Close controls in their title bars, not only to help differentiate them from their modeless brethren, but because the function executed by the close control may be unclear to users.

The cognitive strength of modal dialogs is their rigidly consistent OK and Cancel buttons. In modal dialogs, the OK button means “Accept my input and close the dialog.” In modal dialogs, the Cancel button means “Abandon my input and close the dialog.”

Modeless dialogs frequently have several buttons that immediately invoke various functions. The dialog should not close when one of these function buttons is clicked. It is modeless because it stays around for repet