private void UpdateDisplayedForm(object sender, ItemCheckEventArgs e) { if (editing) { return; } // Only allow one form to be displayed if the user sets a new display value if (e.NewValue != CheckState.Checked) { return; } for (int i = 0; i < CLB_FormDisplayed.Items.Count; i++) { if (i != e.Index) { CLB_FormDisplayed.SetItemChecked(i, false); } else if (sender == CLB_FormDisplayed) { CLB_FormsSeen.SetItemChecked(e.Index, true); // ensure this form is seen } } }