bool on_button_release_event (GdkEventButton *);
bool on_leave_notify_event (GdkEventCrossing *);
bool on_motion_notify_event (GdkEventMotion *);
bool on_button_release_event (GdkEventButton *);
bool on_leave_notify_event (GdkEventCrossing *);
bool on_motion_notify_event (GdkEventMotion *);