Wordpress - Fix custom post type archive and active menu classes

functions.php

<?php
// Taken from http://wordpress.org/support/topic/why-does-blog-become-current_page_parent-with-custom-post-type

function remove_parent_classes($class) {
  // check for current page classes, return false if they exist.
  return ($class == 'active') ? FALSE : TRUE;
}

add_filter('nav_menu_css_class', function ($classes) {
  switch (get_post_type())
  {
    case 'projects':
      $classes = array_filter($classes, "remove_parent_classes");

      // add the current page class to a specific menu item (replace ###).
      if (in_array('menu-our-projects', $classes))
      {
        $classes[] = 'active';
      }
      break;

  }
  return $classes;
});