void amob_FormClosed(object sender, FormClosedEventArgs e) { amob = null; }
private void withdrToolStripMenuItem_Click(object sender, EventArgs e) { if (amob == null) { amob = new AddMoneyOnBank(); amob.MdiParent = this; amob.FormClosed += amob_FormClosed; amob.Show(); } else { amob.Activate(); } }