private void simpleButton2_Click(object sender, EventArgs e) { if (formDayCurve == null || formDayCurve.IsDisposed) { formDayCurve = new FormDayCurve(); //formDayCurve.Owner = this; formDayCurve.Show(); } else { formDayCurve.WindowState = FormWindowState.Maximized; } }