private void tsmiAllShippingOrders_Click(object sender, EventArgs e) { FrmShippingAllOrders frmAllShippingOrders; if (FrmShippingAllOrders.Instance == null) { frmAllShippingOrders = new FrmShippingAllOrders(_myAccessToken); frmAllShippingOrders.MdiParent = this; frmAllShippingOrders.StartPosition = FormStartPosition.CenterScreen; frmAllShippingOrders.Show(); } else { FrmShippingAllOrders.Instance.WindowState = FormWindowState.Normal; FrmShippingAllOrders.Instance.Show(); FrmShippingAllOrders.Instance.BringToFront(); } }