diff --git a/gtk2_ardour/canvas-note-event.h b/gtk2_ardour/canvas-note-event.h
index 748c50efd4..28140267f6 100644
--- a/gtk2_ardour/canvas-note-event.h
+++ b/gtk2_ardour/canvas-note-event.h
@@ -58,7 +58,7 @@ public:
 
 	virtual ~CanvasNoteEvent();
 
-	bool on_event(GdkEvent* ev);
+	virtual bool on_event(GdkEvent* ev);
 
 	bool selected() const { return _selected; }
 	void selected(bool yn);