title: Remove sub menu items
body: <p>I want to remove a few sub menu items from the admin menu in WordPress. I have found the following which can remove certain sub menu items...</p>
  
  <pre><code>add_action( 'admin_menu', 'adjust_the_wp_menu', 999 );
  function adjust_the_wp_menu() {
    $page = remove_submenu_page( 'themes.php', 'widgets.php' );
  }
  </code></pre>
  
  <p>...but what if it is not a standard php such as "themes.php?page=custom-header" that I would like removed.</p>