diff --git a/gtk2_ardour/fft_graph.cc b/gtk2_ardour/fft_graph.cc
index 27d5b06f3e..25f6c6ff29 100644
--- a/gtk2_ardour/fft_graph.cc
+++ b/gtk2_ardour/fft_graph.cc
@@ -420,8 +420,6 @@ FFTGraph::draw_scales (cairo_t* cr)
 void
 FFTGraph::redraw ()
 {
-	Glib::Threads::Mutex::Lock lm  (_a_window->track_list_lock);
-
 	assert (_surface);
 	cairo_t* cr = cairo_create (_surface);
 
@@ -433,6 +431,8 @@ FFTGraph::redraw ()
 		return;
 	}
 
+	Glib::Threads::Mutex::Lock lm  (_a_window->track_list_lock);
+
 	if (!_a_window->track_list_ready) {
 		cairo_destroy (cr);
 		queue_draw ();