diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 2d3d87496c..ebb3cc2404 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -255,6 +255,8 @@ public:
     void Show(bool show);
     bool IsShown() const;
 
+    void SetUserData(wxObject* userData)
+        { delete userData; m_userData = userData; }
     wxObject* GetUserData() const
         { return m_userData; }
     wxPoint GetPosition() const