diff --git a/src/msw/tooltip.cpp b/src/msw/tooltip.cpp
index e5937918f1..ffc0c4cbc9 100644
--- a/src/msw/tooltip.cpp
+++ b/src/msw/tooltip.cpp
@@ -38,10 +38,6 @@
 #include "wx/vector.h"
 #include "wx/msw/private.h"
 
-#ifndef TTTOOLINFO_V1_SIZE
-    #define TTTOOLINFO_V1_SIZE 0x28
-#endif
-
 #ifndef TTF_TRANSPARENT
     #define TTF_TRANSPARENT 0x0100
 #endif