The GTK+ main loop will emit three signals for each GDK event delivered to a widget: one generic event signal, another, more specific, signal that matches the type of event delivered (e.
the Event which triggered this signal
true to stop other handlers from being invoked for the event and to cancel the emission of the second specific event signal. false to propagate the event further and to allow the emission of the second signal. The event_after signal is emitted regardless of the return value.