Invalid form control not focusable
If submitting a form gives errors similar to "An invalid form control with name='shippingmethod.shippingmethod' is not focusable.", usually it's trying to report an error for a component that has been set to display:none or visibility:hidden. This often happens when trying to set up a styled radio/checkbox.
You can use the mixin wh-form-hidenativecontrol instead of display/visibility to fix this, or use something similar to the following styling: