private void historialToolStripMenuItem_Click(object sender, EventArgs e)
 {
     Registros.HistorialForm rhist = new Registros.HistorialForm();
     rhist.MdiParent = this;
     rhist.Show();
 }
 private void HistorialtoolStripButton_Click(object sender, EventArgs e)
 {
     Registros.HistorialForm rhist = new Registros.HistorialForm();
     rhist.MdiParent = this;
     rhist.Show();
 }