diff --git a/include/wx/msw/ole/oleutils.h b/include/wx/msw/ole/oleutils.h
index a628ee50a4..ca8e10c877 100644
--- a/include/wx/msw/ole/oleutils.h
+++ b/include/wx/msw/ole/oleutils.h
@@ -18,9 +18,8 @@
 
 #include "wx/defs.h"
 
-#if wxUSE_NORLANDER_HEADERS
-    #include <ole2.h>
-#endif
+// get IUnknown, REFIID &c
+#include <ole2.h>
 
 // ============================================================================
 // General purpose functions and macros
diff --git a/src/msw/ole/dataobj.cpp b/src/msw/ole/dataobj.cpp
index ded99292e6..6aa1b39762 100644
--- a/src/msw/ole/dataobj.cpp
+++ b/src/msw/ole/dataobj.cpp
@@ -39,16 +39,12 @@
 
 #include "wx/msw/private.h"         // includes <windows.h>
 
-#if wxUSE_NORLANDER_HEADERS
+// for some compilers, the entire ole2.h must be included, not only oleauto.h
+#if wxUSE_NORLANDER_HEADERS || defined(__WATCOMC__)
   #include <ole2.h>
 #endif
+
 #include <oleauto.h>
-
-#ifndef __WIN32__
-  #include <ole2.h>
-  #include <olestd.h>
-#endif
-
 #include <shlobj.h>
 
 #include "wx/msw/ole/oleutils.h"
diff --git a/src/msw/ole/dropsrc.cpp b/src/msw/ole/dropsrc.cpp
index 27dab34ead..fee89b633f 100644
--- a/src/msw/ole/dropsrc.cpp
+++ b/src/msw/ole/dropsrc.cpp
@@ -40,15 +40,11 @@
 
 #include <windows.h>
 
-#if wxUSE_NORLANDER_HEADERS
+// for some compilers, the entire ole2.h must be included, not only oleauto.h
+#if wxUSE_NORLANDER_HEADERS || defined(__WATCOMC__)
     #include <ole2.h>
 #endif
 
-#ifndef __WIN32__
-    #include <ole2.h>
-    #include <olestd.h>
-#endif
-
 #include <oleauto.h>
 
 #include "wx/msw/ole/oleutils.h"