diff --git a/gtk2_ardour/plugin_pin_dialog.h b/gtk2_ardour/plugin_pin_dialog.h
index c4d72c1e3f..38739236d5 100644
--- a/gtk2_ardour/plugin_pin_dialog.h
+++ b/gtk2_ardour/plugin_pin_dialog.h
@@ -93,7 +93,6 @@ private:
 	Gtk::Menu input_menu;
 	Gtk::Table* _sidechain_tbl;
 	Glib::RefPtr<Gtk::SizeGroup> _pm_size_group;
-	Glib::RefPtr<Gtk::SizeGroup> _sc_size_group;
 
 	void plugin_reconfigured ();
 	void update_element_pos ();