Menu Fix for Custom Post Type

gistfile1.php

// Menu Fix for CPT
function remove_parent($var)
{
        // check for current page values, return false if they exist.
        if ($var == 'current_page_item' || $var == 'current_page_parent' || $var == 'current_page_ancestor'  || $var == 'current-menu-item') { return false; }
 
        return true;
}
 
function add_class_to_cpt_menu($classes)
{
        // your custom post type name
        if (get_post_type() == 'products')
        {
                // we're viewing a custom post type, so remove the 'current_page_xxx and current-menu-item' from all menu items.
                $classes = array_filter($classes, "remove_parent");
 
                // add the current page class to a specific menu item.
                if (in_array('menu-item-xx', $classes)) $classes[] = 'current_page_parent';
        }
 
        return $classes;
}
 
add_filter('nav_menu_css_class', 'add_class_to_cpt_menu');