/**
  * Save widget options
  * 
  * @see WP_Widget::update()
  */
 function update($new_instance, $old_instance)
 {
     $settings = $old_instance;
     if (!empty($new_instance['title'])) {
         $settings['title'] = strip_tags($new_instance['title']);
     } else {
         unset($settings['title']);
     }
     if (!empty($new_instance['terms_post_id'])) {
         $terms_post_id = $new_instance['terms_post_id'];
         if ($post = get_post($terms_post_id)) {
             $settings['terms_post_id'] = $post->ID;
         } else {
             if ($post = Affiliates_Utility::get_post_by_title($terms_post_id)) {
                 $settings['terms_post_id'] = $post->ID;
             } else {
                 unset($settings['terms_post_id']);
             }
         }
     }
     return $settings;
 }