you're testing this the wrong way.
the validated entries binding will only have a value if form validation fails
Since the only form element you are validating is the category select list, you should be using the validated entries binding on another form element, and testing in a way that would cause the category list to fail.
you are using required not blank validation on the select list, but you don't have a blank option, meaning that there will always be a selection made, so validation on the category will never fail.
add validation for the email address field, then submit the form without entering an email address, but change the category select list, that would be a more valid text than what you have set up so far....
