diff --git a/gtk2_ardour/luawindow.cc b/gtk2_ardour/luawindow.cc
index 3bc3a4741e..a95376c3a6 100644
--- a/gtk2_ardour/luawindow.cc
+++ b/gtk2_ardour/luawindow.cc
@@ -191,6 +191,7 @@ LuaWindow::hide_window (GdkEventAny *ev)
 
 void LuaWindow::reinit_lua ()
 {
+	ENSURE_GUI_THREAD (*this, &LuaWindow::session_going_away);
 	delete lua;
 	lua = new LuaState();
 	lua->Print.connect (sigc::mem_fun (*this, &LuaWindow::append_text));