private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox1.SelectedIndex == -1)
            {
                return;
            }

            var email = comboBox1.SelectedItem.ToString();

            remitente = listaRemitentes.senders.Where(x => x.email == email).FirstOrDefault();
        }
 private void Limpiar()
 {
     campana.Text            = string.Empty;
     tag.Text                = string.Empty;
     subject.Text            = string.Empty;
     comboBox1.SelectedIndex = -1;
     comboBox2.SelectedIndex = -1;
     listaRemitentes         = new SBRecoverSender();
     remitente               = new SBRecoverSender.Sender();
     tipo = string.Empty;
 }