Adapted Menu Fix for CPT

// Adapted Menu Fix for CPT - http://pastebin.com/T5VAPf1R (discussion on: http://wordpress.org/support/topic/custom-post-type-parent?replies=30#post-1775314)
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() == 'project')
        {
                // 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-127', $classes )) $classes[] = 'current_page_parent';
                elseif (in_array('menu-item-151', $classes )) $classes[] = 'current_page_parent';
        }

        return $classes;
}