Show the result of closing rich message box in the sample.

Improve showing the button which closed the message box by doing it inside the
dialog used for testing it instead of popping up a separate message box just
for this.

And do the same thing for rich message boxes as for the normal ones.

See #16153.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76256 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dialogs/dialogs.h

@@ -216,6 +216,8 @@ protected:
     virtual void AddAdditionalTextOptions(wxSizer *WXUNUSED(sizer)) { }
     virtual void AddAdditionalFlags(wxSizer *WXUNUSED(sizer)) { }
 
+    void ShowResult(int res);
+
     void OnApply(wxCommandEvent& event);
     void OnClose(wxCommandEvent& event);
     void OnUpdateLabelUI(wxUpdateUIEvent& event);
@@ -264,6 +266,8 @@ private:
     wxCheckBox *m_chkNoDefault,
                *m_chkCentre;
 
+    wxStaticText *m_labelResult;
+
     wxDECLARE_EVENT_TABLE();
     wxDECLARE_NO_COPY_CLASS(TestMessageBoxDialog);
 };