Default options form that provides the label widget that all fields should have.
Overrides FieldPluginBase::buildOptionsForm
public function buildOptionsForm(&$form, &$form_state) {
$form['teaser'] = array(
'#type' => 'checkbox',
'#title' => t('Show teaser-style link'),
'#default_value' => $this->options['teaser'],
'#description' => t('Show the comment link in the form used on standard node teasers, rather than the full node form.'),
);
parent::buildOptionsForm($form, $form_state);
}