message: Missed an is
diff: @@ -19,8 +19,8 @@ UnderlineNavLink.defaultProps = {
  }
  UnderlineNavLink.propTypes = {
  - is: PropTypes.oneOfType([PropTypes.string, PropTypes.func]),
  - selected: PropTypes.bool
  + selected: PropTypes.bool,
  + tag: PropTypes.oneOfType([PropTypes.string, PropTypes.func])
  }
  export default withSystemProps(UnderlineNavLink, COMMON)
  