The AUTO3STATE resource-definition statement creates an automatic three-state check box. The control is an open box with the given text positioned to the right of the box. When chosen, the box automatically advances between three states: checked, unchecked, and disabled (grayed). The control sends a message to its parent whenever the user chooses the control.
AUTO3STATE text, id, x, y, width, height [, style [, extended-style]]
If you do not specify a style, the default style is BS_AUTO3STATE | WS_TABSTOP.
For more information on the text, id, x, y, width, height, style, and extended-style parameters, see Common Control Parameters.
AUTOCHECKBOX, CHECKBOX, CONTROL, STATE3