add tests for the remaining message box flags (wxNO_DEFAULT and wxCENTRE)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@55528 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dialogs/dialogs.h

@@ -181,6 +181,7 @@ private:
     void OnApply(wxCommandEvent& event);
     void OnClose(wxCommandEvent& event);
     void OnUpdateLabelUI(wxUpdateUIEvent& event);
+    void OnUpdateNoDefaultUI(wxUpdateUIEvent& event);
 
     enum
     {
@@ -207,6 +208,9 @@ private:
 
     wxRadioBox *m_icons;
 
+    wxCheckBox *m_chkNoDefault,
+               *m_chkCentre;
+
     DECLARE_EVENT_TABLE()
     DECLARE_NO_COPY_CLASS(TestMessageBoxDialog)
 };