private void checkedListBoxOwner_ItemCheck(object sender, ItemCheckEventArgs e) { if (filterListAllowed) { // update shownOwners string owner = checkedListBoxOwner.Items[e.Index].ToString(); if (e.NewValue == CheckState.Unchecked) { creatureCollection.hiddenOwners.Add(owner); } else { creatureCollection.hiddenOwners.Remove(owner); } filterLib(); } }