I have a form in which there the user is required to enter either a postal code OR select a city in order to do a search. If they fail to enter either and submit the form, currently the form highlights both fields in red. Some members of my team think this is confusing to the user.
My suggestion was that as soon as the user selects one field, the other field's highlight disappears. The fields are next to each other on the form. Is this the best way to handle the error validation or is there a better way to avoid confusion for the users?