Event handlers provide an efficient means of performing low level input handling which bypasses the translation tables of the widget. They are particularly suited to high-volume events. A translation and associated action, however, can do almost anything that an event handler can do but may be easier to maintain.
Event handlers, unlike the other Xt procedures, are defined for individual widgets rather than for the whole application.
Add an event handler by selecting the widget whose events are wanted and then choosing "Event Handlers..." from the Widget menu.
See also: