I was trying to add a specific class to the admin section. I created a new top-level menu page and now I want to add a specific class to this top-level menu and its submenu items.

What I have tried so far is that I used WP_Screen to get the data of the current screen.

If I check the submenu page and I did var_dump(get_current_screen()). It shows every detail.

But now the case is that If I use get_current_screen() with admin_body_class why it doesn't work.

As far as I know, the hook is early called before the submenu page details are loaded.

Now I want to ask, how it is possible to check if the submenu has a specific parent base,

Here is the code that I tried so far.

add_filter('admin_body_class', 'tw_admin_body_class');
function tw_admin_body_class( $classes ) {
    $screen = get_current_screen();
    if (  $screen->parent_base == 'tw-top' )  {
        return $classes . ' raashid';

But parent_base is set to null. Any idea how to add class to submenu pages if it is under the specific top-level menu.

1 Answer 1


But parent_base is set to null.

Yes, because by the time admin_body_class is fired, WordPress hasn't yet set the parent_base value.

And it's only set after the <body> tag is actually outputted. More specifically, it's set only after the <div id="wpbody" role="main"> as you can see here in wp-admin/admin-header.php.

Any idea how to add class to submenu pages if it is under the specific top-level menu.

You can use the admin_body_class hook, but instead of the $screen->parent_base, use $screen->id which is the hook name returned by add_menu_page() as well as add_submenu_page().

And to get that hook name, you should or would want to use get_plugin_page_hook().

So for example:

  • If I added my top-level and sub menus like so:

    // Top-level menu: "Test menu"
    add_menu_page( 'Test', 'Test menu', 'manage_options', 'test', 'some_function' );
    // Submenu: "Test submenu"
    add_submenu_page( 'test', 'Submenu Page', 'Test submenu', 'manage_options',
        'test-submenu', 'some_function_2' );
  • Then I can add the custom CSS class like so:

    add_filter( 'admin_body_class', 'my_admin_body_class' );
    function my_admin_body_class( $classes ) {
        $screen = get_current_screen();
        if ( get_plugin_page_hook( 'test', '' ) === $screen->id ) {
            $classes .= ' foo-class';
        elseif ( get_plugin_page_hook( 'test-submenu', 'test' ) === $screen->id ) {
            $classes .= ' bar-class';
        return $classes; // *always return this

    Note that I emphasized the return $classes; because in your tw_admin_body_class() function, the $classes is only returned if your conditional returns a true.

And actually, the plugin page hook is added by default to the <body> tag of the menu/admin page as well as the top-level menu item (<li> tag), e.g. <body class="... toplevel_page_test ..."> on my "Test" admin page, so you could probably just make use of that class?

  • 1
    thanks for your help. I have a specific need to add body class. Otherwise, I knew the CSS option exists. Anyway thanks for your help. Commented Feb 4, 2021 at 15:17
  • In that case, then I removed the CSS code, but I retained the "make use of that class" part. :)
    – Sally CJ
    Commented Feb 5, 2021 at 4:27

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