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