/** For testing. */
        public static void Main()
        {
            HistoryDialog hd = new HistoryDialog();

            _test_string(hd);
            Application.Run(hd);
        }
        private static void _test_string(HistoryDialog hd)
        {
            String s = "This is a long message.";

            for (int i = 0; i < 100; i++)
            {
                hd.AddMessage(s);
            }
        }