diff --git a/include/wx/osx/core/private.h b/include/wx/osx/core/private.h
index 7ffa154e10..7484906d58 100644
--- a/include/wx/osx/core/private.h
+++ b/include/wx/osx/core/private.h
@@ -769,7 +769,7 @@ public :
         return false ;
     }
 
-    bool CanSetTransparent()
+    virtual bool CanSetTransparent()
     {
         return false;
     }