class Capybara::RackTest::Node

def disabled?
  return true if string_node.disabled?
  if %w[option optgroup].include? tag_name
    find_xpath("parent::*[self::optgroup or self::select]")[0].disabled?
  else
    !find_xpath("parent::fieldset[@disabled] | ancestor::*[not(self::legend) or preceding-sibling::legend][parent::fieldset[@disabled]]").empty?
  end
end