pointless use of count()

        $options['custom_url'] = t('Custom URL');
        if (count($options)) {
          $form['link_display'] = array(
            '#type' => 'radios',
            '#options' => $options,
            '#description' => t("Which display to use to get this display's path for things like summary links, rss feed links, more links, etc."),
            '#default_value' => $this->get_option('link_display'),
          );
        }

$options can't possibly be empty.

This is in views_plugin_display::options_form().