The push-button gadget provides press-to-activate switch behavior.
arm-callback will be invoked when the push button becomes armed (such as when the pointer moves into it, or a pointer button is pressed over it). When the button is actually activated (by releasing the pointer button over it), activate-callback will be invoked. Finally, disarm-callback will be invoked after activate-callback , or when the pointer is moved outside of the button.
Summary: The class that implements an abstract push button. It is a subclass of active-gadget and labelled-gadget-mixin .
Summary: This initializes the "show as default" property for the gadget.
Summary: Returns the "show as default" property for the push button gadget. When t , the push button will be drawn with a heavy border, which indicates that this button is the "default operation."
Summary: The class that implements a portable push button; a subclass of push-button .
Common Lisp Interface Manager 2.0 User's Guide - 7 Aug 2017