<vaadin-combo-box> not populated with polymer template on vaadin 13

I have been several days with a problem I am not able to solve.
I am triying to make my own web component using a polymer 2 template on vaadin 13.
It is a basic template, it only shows a combobox, the problem is that the combobox is not populated with values.
I am newbie with that so the solution can be very stupid. Thanks in advance.
My code:

''' And the java class: ''' @Tag("hello-world") @HtmlImport("hello-world.html") public class HelloWorld extends PolymerTemplate {
private ComboBox<String> name;

 * Creates the hello world template.
public HelloWorld() {
    name = new ComboBox<String>();


Hi! The problem is the first line in your constructor:

name = new ComboBox<String>();

Just remove this line and it should work. When you use @Id, the component is initialized automatically for you based on the Polymer template. So the framework will create the ComboBox for you automatically. If you change this reference to a new ComboBox, it will not point to the same component in the template any more.

It works!!!

Lot of thanksss!