private void ctxtSystemInformation_Click(object sender, EventArgs e) { if (lstClients.SelectedItems.Count != 0) { Client c = (Client)lstClients.SelectedItems[0].Tag; if (c.Value.frmSI != null) { c.Value.frmSI.Focus(); return; } frmSystemInformation frmSI = new frmSystemInformation(c); frmSI.Show(); } }