Column view become blank when sorted

Platform
1

When click column header binded to sorter, column view became blank if selected item is out of sight.
column_view

pub fn make_process_list() -> ColumnView {
    let store = gio::ListStore::with_type(ProcessObject::static_type());

    for process in get_processes() {
        store.append(&process);
    }

    let list_model: gio::ListModel = store.upcast();
    let sort_model = gtk4::SortListModel::new(Some(list_model), None::<gtk4::Sorter>);
    let selection_model = SingleSelection::new(Some(sort_model));

    let column_view = ColumnView::builder()
        .model(&selection_model)
        .show_row_separators(true)
        .show_column_separators(true)
        .build();

    add_column(&column_view, "PID", "pid");
    add_column(&column_view, "User", "user");
    add_column(&column_view, "Name", "name");
    add_column(&column_view, "Command", "command");

    let view_sorter = column_view.sorter();
    let model = column_view.model().unwrap();
    let selection_model = model.downcast_ref::<SingleSelection>().unwrap();
    let list_model = selection_model.model().unwrap();
    let sort_model = list_model.downcast_ref::<SortListModel>().unwrap();
    sort_model.set_sorter(view_sorter.as_ref());

    column_view.sorter().expect("no sorter").connect_changed({
        move |_sorter, _change| {
            println!("sorter changed");
        }
    });
    column_view
}

fn add_column(column_view: &ColumnView, title: &str, property: &'static str) {
    let factory = SignalListItemFactory::new();

    factory.connect_setup(move |_, list_item| {
        let list_item = list_item.downcast_ref::<gtk4::ListItem>().unwrap();
        let label = Label::builder()
            .xalign(0.0)
            .margin_start(4)
            .margin_end(4)
            .build();
        list_item.set_child(Some(&label));
        let item = list_item.property_expression("item");
        item.chain_property::<ProcessObject>(property)
            .bind(&label, "label", Widget::NONE);
    });
    
    let sorter = gtk4::CustomSorter::new(move |a, b| {
        let a_val = a.property::<String>(property);
        let b_val = b.property::<String>(property);
        if a_val.is_empty() || b_val.is_empty() {
            return gtk4::Ordering::Equal;
        }
        match a_val.cmp(&b_val) {
            std::cmp::Ordering::Less => gtk4::Ordering::Smaller,
            std::cmp::Ordering::Equal => gtk4::Ordering::Equal,
            std::cmp::Ordering::Greater => gtk4::Ordering::Larger,
        }
    });
    let column = ColumnViewColumn::builder()
        .title(title)
        .factory(&factory)
        .sorter(&sorter)
        .build();

    column_view.append_column(&column);
}
2

I have included a simple example here that shows the sorter: GTKColumnView / Sorter no works - #7 by chrisaw

3

Thank you!
This is more general question: as you can see in my video sorter works. First click on it works fine. List become blank only on second click.
It solved itself when i put wrapping ScrollView in Clamp.