private void facturacionToolStripMenuItem_Click(object sender, EventArgs e)
{
RFactura Abrir = new RFactura();
Abrir.Show();
}
private void reporteFacturasToolStripMenuItem_Click(object sender, EventArgs e)
{
var Formulario = Application.OpenForms.OfType <RFactura>().FirstOrDefault();
RFactura Entrada = Formulario ?? new RFactura();
}