diff --git a/gtk2_ardour/midi_list_editor.h b/gtk2_ardour/midi_list_editor.h
index 79db6d1335..e24a3c592b 100644
--- a/gtk2_ardour/midi_list_editor.h
+++ b/gtk2_ardour/midi_list_editor.h
@@ -26,6 +26,8 @@
 #include <gtkmm/table.h>
 #include <gtkmm/treeview.h>
 
+#include "temporal/beats.h"
+
 #include "ardour/session_handle.h"
 
 #include "ardour_window.h"