+#include "gtkmm2ext/persistent_tooltip.h"
+
+class KnobPersistentTooltip : public Gtkmm2ext::PersistentTooltip
+{
+public:
+ KnobPersistentTooltip (Gtk::Widget* w);
+
+ void start_drag ();
+ void stop_drag ();
+ bool dragging () const;
+
+private:
+ bool _dragging;
+};
+