diff --git a/include/wx/defs.h b/include/wx/defs.h
index 9f088c3832..b39d3cc7b4 100644
--- a/include/wx/defs.h
+++ b/include/wx/defs.h
@@ -1441,6 +1441,7 @@ enum wxBorder
 #define wxSL_BOTTOM          0x0200
 #define wxSL_BOTH            0x0400
 #define wxSL_SELRANGE        0x0800
+#define wxSL_INVERSE         0x1000
 
 /*
  * wxScrollBar flags