private void deleteButton_Click(object sender, RoutedEventArgs e)
        {
            YesNoWindow yy = new YesNoWindow("Do you want to delete this task ?");

            yy.ShowDialog();
            if (yy.ans == true)
            {
                bolayer.task_delete(tasknow);
                ftp.deletefile(tasknow.folder);
                bolayer.load_task_form_server();
            }
        }