Combo box with template renderer

Hi all,

I made a Combo Box with TemplateRenderer that indicate following souce coude, however, it is not effective to store the selected value via binder.
Please provide any advice me to correct.

Thanks
Ippei

ComboBox<Comment> commentField = new ComboBox<>();
ItemFilter<Comment> filter = (item, filterString) -> item.getId().toLowerCase().contains(filterString.toLowerCase()) ;
commentField.setItems(filter, commentEntity);
commentField.setItemLabelGenerator(Comment::getId);
commentField.setRenderer(TemplateRenderer.<Comment> of(
        "<div>[[item.id]
]<br><small>[[item.description]
]</small></div>")
        .withProperty("id", Comment::getId)
        .withProperty("description", Comment::getDescription));
binder.bind(commentField, "id");