public virtual signal bool visibility_notify_event (EventVisibility event)
Warning: visibility_notify_event is deprecated since "3.12".
The visibility_notify_event will be emitted when the
widget's window is obscured or unobscured.
Modern composited windowing systems with pervasive transparency make it impossible to track the visibility of a window reliably, so this signal can not be guaranteed to provide useful information.
the EventVisibility which triggered this signal.
true to stop other handlers from being invoked for the event. false to propagate the event further.