void dap_FormClosed(object sender, FormClosedEventArgs e) { dap = null; }
private void checkAllPerformanceInformationToolStripMenuItem_Click(object sender, EventArgs e) { if (dap == null) { dap = new DeleteAnPerformance(); dap.MdiParent = this; dap.FormClosed += dap_FormClosed; dap.Show(); } else { dap.Activate(); } }