diff --git a/src/widgets/MultiDialog.cpp b/src/widgets/MultiDialog.cpp
index ae7ab4328..2796a23cd 100644
--- a/src/widgets/MultiDialog.cpp
+++ b/src/widgets/MultiDialog.cpp
@@ -19,6 +19,7 @@ for each problem encountered, since there can be many orphans.
 *//*******************************************************************/
 
 #include "../Audacity.h"
+#include "../AudacityApp.h"
 
 #include "MultiDialog.h"