Navigation menu order

Changing the order of navigation menu items by programming code doesn't work.

For example in my extension I have a navigation item which I want to show at the top of the search menu. So I give it a weight of -100. (A lower weight means sorting to top, a higher weight sorting to bottom).

_testnav_civix_insert_navigation_menu($menu, 'Search', array(
    'label' => E::ts('Test Navigation'),
    'name' => 'test_navigation',
    'url' => 'civicrm/mypage',
    'permission' => 'access CiviCRM',
    'operator' => 'OR',
    'separator' => 0,
    'weight' => -100
  ));
  _testnav_civix_navigationMenu($menu);
}

However the code above does't work.

Additional details

CiviCRM Version 5.36.alpha1 Drupal 8