gnome-sharp 2.20.0.0 Gtk# is thread aware, but not thread safe; See the Gtk# Thread Programming for details. To be added. To be added. Event handler. The event utilizes this delegate: Event data is passed via the parameter. To attach a to an event, add the CancelClickedHandler instance to the event. The methods referenced by the CancelClickedHandler instance are invoked whenever the event is raised, until the CancelClickedHandler is removed from the event. System.Delegate System.Void