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