diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 3f7d8bc354..7f7481fed3 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -112,7 +112,7 @@ public:
     wxWindow *GetWindow() const
         { return m_window; }
     void SetWindow( wxWindow *window )
-        { m_window = window; }
+        { m_window = window; m_minSize = window->GetSize(); }
     wxSizer *GetSizer() const
         { return m_sizer; }
     void SetSizer( wxSizer *sizer )