On Tertiary links on Drupal I described a simple approach to display the “tertiary” menu (childrens of secondary menus) on Drupal 5.x. This is an useful but sometimes limiting approach, since the secondary menu disappears when tertiary menu is displayed.

This is an alternative workaround made using a customized menu_tree function:

template.php:

function custom_menu_tree_secondary($pid = 1) {
  $menu = menu_get_menu();
  $output = '';

  if (isset($menu['visible'][$pid]) && $menu['visible'][$pid]['children']) {
    foreach ($menu['visible'][$pid]['children'] as $mid) {
      $type = isset($menu['visible'][$mid]['type'])
? $menu['visible'][$mid]['type'] : NULL;
      $children = isset($menu['visible'][$mid]['children'])
? $menu['visible'][$mid]['children'] : NULL;
      # display only the children menu of the current menu
      if(menu_in_active_trail($mid)) {
      	$output .= theme('menu_tree', $mid);
      }
    }
  }
  return $output;
}

page.tpl.php (in place of standard $secondary block):

<div id="secondary">
<?php if ($secondary_links): ?>
<?php echo tools_menu_tree_secondary(variable_get('menu_primary_menu', 0));?>
<?php endif; ?>
</div>

Tested on:

• Drupal 5.x
• Zen subtheme