[@mica123 Participant 11 years ago]

When I use this code without the
if(is_bbpress() && $args->theme_location == 'sub-header-menu')

it works but I get the links on both menus. Below is the code I tried to use for the second menu only – the second menu is called Logins – I tried to use both sub-header-menu or logins.
I tried your suggestion with both as well.

add_filter( 'wp_nav_menu_items', 'my_nav_menu_login_link' );
function my_nav_menu_login_link($menu) {
    //uncomment the next line if you only want login on bbpress pages

   if(is_bbpress() && $args->theme_location == 'sub-header-menu')
    if (is_user_logged_in()) {
        //set the $url on the next line to the page you want users to go back to when they logout
        $url = '$url = 'http://www.mysite.com/forums';
        $url2=wp_logout_url($url) ;
        $loginlink = '<li><a title="Logout" href="'.$url2.'">Logout</a></li>';
        }
    else {
        $current_user = wp_get_current_user();
        $user=$current_user->user_login ;
        //set $page on the next line = the permalink for your login page
        $page=''login' ;
        $loginlink = '<li><a href="/'.$page.'/">Login</a></li>';
                }
     //uncomment out the next lines if you only want login on bbpress pages
   }
    else {
   $loginlink="" ;
      }
        $menu = $menu . $loginlink;
        return $menu;
        }