Hi Tatu,
actually i think I found a bug using FilterMode.RESETVALUE together with a simple SortComparator, because in Method sortDestinationList(...) the filter is set after setting the value from the sortboxes. This leads to the value being empty after adding an entry to the non empty right side.
I think the filter should set directly after the fetch from data provider is done.
This occurres in 23.3.30 and 24.3.2
TwinColSelect<String> select = new TwinColSelect<>();
select.setFilterMode(FilterMode.RESETVALUE);
select.setItems("Eins","Zwei","Drei");
select.getListDataView().setSortComparator((o1,o2) -> o1.compareTo(o2));
add(select);