Menu disable causes weird behavior

I have a module that creates a menu entry. If I disable the menu entry, it completely disappears from admin>build>menu so it cannot be re-enabled. Even if I disable, uninstall, and re-enable the module, the item never comes back to the admin>build>menu list. However, it shows back up in the Navigation menu and works. I also do not see it in the menu table when I browse it with PhpMyAdmin.

  if ($may_cache) {
    ...
  }
  else {
    $items[] = array(
      'path' => 'taxonomy_browser',
      'title' => t('Category Browser'),
      'access' => user_access(variable_get('taxonomy_browser_need_perm', false) ? 'access taxonomy browser' : 'access content'),
      'callback' => 'taxonomy_browser_page',
      'description' => t('Find content on your own terms.'),
      'type' => MENU_NORMAL_ITEM,
      );
  }

I have tried all kinds of combinations and cannot get it back in the admin list. I forced "menu_rebuild". I emptied all the cache tables. I shut down the browser session. I shut down Apache. None of these works.

Why would disabling the menu item make it disappear? And why can I not get it back at all?