diff --git a/include/wx/event.h b/include/wx/event.h
index 46d21a54ff..5ce6242d57 100644
--- a/include/wx/event.h
+++ b/include/wx/event.h
@@ -1797,6 +1797,7 @@ public:
 
     enum
     {
+        IsBackward = 0x0000,
         IsForward = 0x0001,
         WinChange = 0x0002
     };