private void MenuItem_Click_add(object sender, RoutedEventArgs e)
        {
            AddTesterWindow addTesterWindow = new AddTesterWindow();

            addTesterWindow.ShowDialog();
        }
        private void pbTester_Click(object sender, RoutedEventArgs e)
        {
            AddTesterWindow addTesterWindow = new AddTesterWindow();

            addTesterWindow.ShowDialog();
        }