generate the correct events in the native MSW version of wxCalendarCtrl

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@53007 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/calctrl.h

@@ -56,6 +56,8 @@ protected:
     virtual bool MSWOnNotify(int idCtrl, WXLPARAM lParam, WXLPARAM *result);
 
 private:
+    wxDateTime m_date;
+
     DECLARE_DYNAMIC_CLASS(wxCalendarCtrl)
     DECLARE_NO_COPY_CLASS(wxCalendarCtrl)
 };