Index: gtk2_ardour/plugin_ui.cc
===================================================================
--- gtk2_ardour/plugin_ui.cc	(revision 12381)
+++ gtk2_ardour/plugin_ui.cc	(working copy)
@@ -584,6 +584,9 @@
 			warning << string_compose(_("Plugin preset %1 not found"),
 						  _preset_combo.get_active_text()) << endmsg;
 		}
+	} else {
+		// blank selected = no preset
+		plugin->clear_preset();
 	}
 }
 
@@ -736,6 +739,8 @@
 		preset_labels.push_back (i->label);
 	}
 
+	preset_labels.push_back("");
+
 	set_popdown_strings (_preset_combo, preset_labels);
 
 	--_no_load_preset;
@@ -759,6 +764,7 @@
 void
 PlugUIBase::update_preset_modified ()
 {
+
 	if (plugin->last_preset().uri.empty()) {
 		_preset_modified.set_text ("");
 		return;
Index: libs/ardour/ardour/plugin.h
===================================================================
--- libs/ardour/ardour/plugin.h	(revision 12381)
+++ libs/ardour/ardour/plugin.h	(working copy)
@@ -182,6 +182,7 @@
 	void remove_preset (std::string);
 
 	virtual bool load_preset (PresetRecord);
+	void clear_preset ();
 
 	const PresetRecord * preset_by_label (const std::string &);
 	const PresetRecord * preset_by_uri (const std::string &);
Index: libs/ardour/plugin.cc
===================================================================
--- libs/ardour/plugin.cc	(revision 12381)
+++ libs/ardour/plugin.cc	(working copy)
@@ -321,6 +321,16 @@
 	return true;
 }
 
+void
+Plugin::clear_preset ()
+{
+	_last_preset.uri = "";
+	_last_preset.label = "";
+	_parameter_changed_since_last_preset = false;
+
+	PresetLoaded (); /* EMIT SIGNAL */
+}
+
 /** @param val `plugin' value */
 void
 Plugin::set_parameter (uint32_t which, float val)