}
-PannerBar::PannerBar (Gtk::Adjustment& adj, PBD::Controllable& c)
+PannerBar::PannerBar (Gtk::Adjustment& adj, boost::shared_ptr<PBD::Controllable> c)
: BarController (adj, c, sigc::ptr_fun (null_label_callback))
{
set_style (BarController::Line);