Updating a dossier field should only validate the updated field
After adding more than one required fields to a dossier definition it is not possible to update an instance of that definition with these two empty fields because the dossier is validated completely which triggers a validation error for each field. The fix is to only validate the updated field on update. On creation we still validate the whole dossier to enforce a valid dossier on creation.
The second problem is that validation errors in the dossier field add/edit dialog are not shown correctly.