selenium with vaadin touchkit

Trying to use selenium for testing the vaadin touchkit application it seems that everytime there is a deployment the fieldid increases by 1 (which is dynamic) and not static. Is there anything that requires to be done from the application point of view?

Also is selenium the best to test the application or the testbench?

Simple, quick, google search would return this:
https://aadin.com/blog/-/blogs/testing-vaadin-applications-with-selenium-vs-testbench