When you create a custom dialog box, you can specify how it handles keyboard shortcuts.
Some keyboard shortcuts are common to all dialog boxes. For example, the Tab key generally enables users to move from tile to tile, and the Spacebar allows users to turn toggles off or on. Each active tile should be a tab stop (the default).
Two keys commonly act as accelerator keys. The accept key (usually the Enter key) accepts the dialog box and values entered. The cancel key (Esc), discards the dialog box and the values. When AutoCAD first displays a dialog box, one of its tiles has the initial keyboard focus. What the user enters affects this tile until the user moves focus to another tile.
Pressing Tab moves focus from tile to tile or you can enter one of the keyboard shortcuts known as mnemonic keystrokes. Moving between tiles changes focus but does not make a selection. Pressing Enter is required to perform the action of the tile that has focus after it is selected. For some kinds of tiles, a double-click is equivalent to pressing Enter.