diff --git a/src/generic/scrlwing.cpp b/src/generic/scrlwing.cpp
index c17909a709..43f061c2d6 100644
--- a/src/generic/scrlwing.cpp
+++ b/src/generic/scrlwing.cpp
@@ -40,6 +40,7 @@
 #include "wx/scrolwin.h"
 #include "wx/panel.h"
 #include "wx/timer.h"
+#include "wx/sizer.h"
 
 #ifdef __WXMSW__
     #include <windows.h> // for DLGC_WANTARROWS