diff --git a/src/TrackPanelCell.h b/src/TrackPanelCell.h
index 39750c461..09199c37c 100644
--- a/src/TrackPanelCell.h
+++ b/src/TrackPanelCell.h
@@ -11,6 +11,8 @@ Paul Licameli
 #ifndef __AUDACITY_TRACK_PANEL_CELL__
 #define __AUDACITY_TRACK_PANEL_CELL__
 
+#include "Audacity.h"
+
 #include "MemoryX.h"
 
 class AudacityProject;