Combobox and text area form validation error not displayed in Chrome/Edge

[m-akinc]

🐛 Bug Report

In Chrome/Edge, a missing value on a required combobox or text area properly blocks form submission and updates the control's validity flags, but the native, visual indicator of the validation error (see screenshot below) is not shown. Instead, an error is printed to the console: "An invalid form control with name='' is not focusable."

💁 Possible Solution

Presumably, something is trying to focus the host element, though it delegates focus to the shadow DOM. The error comes from a call to form.requestSubmit() in the FAST button code, which we cannot debug into. Things work properly in Firefox.