private void clientesToolStripMenuItem_Click(object sender, EventArgs e)
 {
     using (frmClientes ventanaClientes = new frmClientes())
         ventanaClientes.ShowDialog();
 }
 private void btn_Cliente_Click(object sender, EventArgs e)
 {
     using (frmClientes ventanaClientes = new frmClientes())
         ventanaClientes.ShowDialog();
 }