MultiSelectListBox filter does not work correctly

Flow
1

I have a TextField that also implements Predicate
public class FilterStringTextField<T> extends TextField implements SerializablePredicate<T>

so it can be used in
MultiSelectListBox.getListDataView().setFilter(...)

Everytime something is typed in the textfield, it calls setFilter. The implementation of predicate may vary, but usually is “if the textfield is empty return true, else do a case insensitive contains”. This initially seems to work perfectly. So first all are shown:

2025-05-27 22 44 31 all
2025-05-27 22 44 31 all715×879 43.2 KB

Then the filter is set, a subset of rows are shown, and the 3rd row is selected.

2025-05-27 22 45 00 filtered
2025-05-27 22 45 00 filtered714×771 36.9 KB

And then the filter textfield is cleared, which makes the predicate always return true so all are shown again:

2025-05-27 22 45 18 filter cleared
2025-05-27 22 45 18 filter cleared715×692 34.8 KB

But the 3rd row is selected! Which is the wrong element. It keeps the presention index, not the model index, selected when changing the filter.

Vaadin 24.7.5.

2

Have you implemented hashCode() and equals()? I haven’t tried MultiSelectListBox, but other Vaadin components such as grid and select won’t work correctly if those methods aren’t producing a correct result.

3

Yes I have. But if equals and hashcode were the cause, then the behavior would not be as predictable as it is now: it always keeps the presentation model index selected, not the data model index.

4

Could be a bug, but difficult to say without seeing some code. You could open an issue with a reproduction here: GitHub · Where software is built

5

Will do, but this code shows the problem:


@Route("/test")
public class TestView extends VerticalLayout {

    public TestView() {
        TextField textField = new TextField();
        textField.setClearButtonVisible(true);
        textField.setValueChangeMode(ValueChangeMode.EAGER);
        add(textField);

        MultiSelectListBox<String> listBox = new MultiSelectListBox<>();
        listBox.setItems("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten");
        listBox.setSelectionPreservationMode(SelectionPreservationMode.PRESERVE_EXISTING);
        add(listBox);

        ListBoxListDataView<String> listDataView = listBox.getListDataView();
        textField.addValueChangeListener(e -> listDataView.setFilter((SerializablePredicate<String>) s -> {
            String filterContent = textField.getValue().toLowerCase();
            return filterContent.isEmpty() || s.toLowerCase().contains(filterContent);
        }));
    }
}
6