private void grupoToolStripMenuItem_Click(object sender, EventArgs e)
 {
     if (gurpo == null)
     {
         gurpo             = new Gurpo();
         gurpo.MdiParent   = this;
         gurpo.FormClosed += new FormClosedEventHandler(CerrarFormaGrupo);
         gurpo.Show();
     }
     else
     {
         gurpo.Activate();
     }
 }
 private void CerrarFormaGrupo(object sender, FormClosedEventArgs e)
 {
     gurpo = null;
 }