diff --git a/gtk2_ardour/vst_plugin_ui.cc b/gtk2_ardour/vst_plugin_ui.cc
index 3b1f999a7c..56b8344927 100644
--- a/gtk2_ardour/vst_plugin_ui.cc
+++ b/gtk2_ardour/vst_plugin_ui.cc
@@ -60,7 +60,7 @@ VSTPluginUI::~VSTPluginUI ()
 }
 
 void
-VSTPluginUI::preset_selected (Plugin::PresetRecord preset)
+VSTPluginUI::preset_selected (ARDOUR::Plugin::PresetRecord preset)
 {
 #ifdef GDK_WINDOWING_X11
 	_socket.grab_focus ();