Drupal 6: Custom Menu not Expanding when Parent (generated by views) is selected
Five lines of code placed in a views template file solved the issue:

 &lt;?php
    $path = drupal_get_path_alias(check_plain($_GET['q']));
    $menu_item = menu_get_item($path);
    $menu_item['href'] = $path;
    if($path &amp;&amp; $menu_item) {
      menu_set_item(NULL, $menu_item);
    }
  ?&gt;