An invalid form control with name='' is not focusable

[Nashorn]

This issue occurs on Chrome if a form field fails validation, but due to the respective invalid control not being focusable the browser's attempt to display the message "Please fill out this field" next to it fails as well.

TL;DR:
To solve the problem, if you have a button on your page that does something else other than submit or reset, always remember to do add type='button':
<button type="button">

REFERENCE:
https://stackoverflow.com/questions/22148080/an-invalid-form-control-with-name-is-not-focusable

A form control may not be focusable at the time validation is triggered for several reasons. The two scenarios described below are the most prominent causes:

The field is irrelevant according to the current context of the business logic. In such a scenario, the respective control should be disabled or removed from the DOM or not be marked with the required attribute at that point.

Premature validation may occur due to a user pressing ENTER key on an input. Or a user clicking on a button/input control in the form which has not defined the type attribute of the control correctly. If the type attribute of a button is not set to button, Chrome (or any other browser for that matter) performs a validation each time the button is clicked because submit is the default value of a button's type attribute.