diff --git a/src/common/helpbase.cpp b/src/common/helpbase.cpp
index 2a1b47943c..1468954b39 100644
--- a/src/common/helpbase.cpp
+++ b/src/common/helpbase.cpp
@@ -25,6 +25,7 @@
 #endif
 
 #include "wx/helpbase.h"
+#include "wx/app.h"
 
 #ifdef __WXMSW__
 #include "wx/msw/private.h"