Every widget has a translation table that defines how a widget will respond to particular events. These events can enable one or more actions.
Full details of each widgets response can be found in the Motif Reference manuals which should be readily at hand.
An example of part of the translation table for the push button is:
BSelect Press corresponds to a left mouse pressed down and the action is the Arm() function being called which cause the display of the button to appear as it was depressed. If the mouse is clicked (pressed and released) then Activate() and Disarm() functions are called which will cause the button to be reactivated.
Keyboard events can be listed in the table as well to provide facilities such as hot keys, function/numeric select keys and help facilities. These can provide short cuts to point and click selections.
Examples include: KActivate - typically the return key, KHelp - the HELP or F1 key.
There are many other default events - see reference manuals for details.