Index: gtk2_ardour/lv2_plugin_ui.cc
===================================================================
--- gtk2_ardour/lv2_plugin_ui.cc	(revision 14055)
+++ gtk2_ardour/lv2_plugin_ui.cc	(working copy)
@@ -332,6 +332,18 @@
 {
 	stop_updating (0);
 
+	if (_ardour_buttons_box) {
+		_ardour_buttons_box->remove (focus_button);
+		_ardour_buttons_box->remove (bypass_button);
+		_ardour_buttons_box->remove (delete_button);
+		_ardour_buttons_box->remove (save_button);
+		_ardour_buttons_box->remove (add_button);
+		_ardour_buttons_box->remove (_preset_combo);
+		_ardour_buttons_box->remove (_preset_modified);
+		remove (*_ardour_buttons_box);
+		_ardour_buttons_box = NULL;
+	}
+
 	if (_gui_widget) {
 		remove (*_gui_widget);
 		_gui_widget = NULL;