private void toolStripButton1_Click(object sender, EventArgs e)
        {
            SuppliersForm suppliersForm = new SuppliersForm(suppliers);

            suppliersForm.Show();
        }
        private void suppliersToolStripMenuItem_Click(object sender, EventArgs e)
        {
            SuppliersForm suppliersForm = new SuppliersForm(suppliers);

            suppliersForm.Show();
        }