diff --git a/include/wx/os2/notebook.h b/include/wx/os2/notebook.h
index 6dcd73855b..39415272d8 100644
--- a/include/wx/os2/notebook.h
+++ b/include/wx/os2/notebook.h
@@ -14,9 +14,10 @@
 // ----------------------------------------------------------------------------
 // headers
 // ----------------------------------------------------------------------------
-#ifndef   _DYNARRAY_H
-  #include <wx/dynarray.h>
-#endif  //_DYNARRAY_H
+
+#include "wx/dynarray.h"
+#include "wx/string.h"
+#include "wx/control.h"
 
 // ----------------------------------------------------------------------------
 // types