title: ACF options add submenu with a callback function
body: <p>I want to add a custom submenu to option page so that I can render page with callback function I add.  If I create acf_add_options_sub_page I must use the acf field to generate the options page.</p>
  <pre><code>if( function_exists('acf_add_options_page') ) {
      
      acf_add_options_page(array(
          'page_title'    =&gt; 'Theme General Settings',
          'menu_title'    =&gt; 'Theme Settings',
          'menu_slug'     =&gt; 'theme-general-settings',
          'capability'    =&gt; 'edit_posts',
          'redirect'      =&gt; false
      ));
      
      acf_add_options_sub_page(array(
          'page_title'    =&gt; 'Theme Header Settings',
          'menu_title'    =&gt; 'Header',
          'parent_slug'   =&gt; 'theme-general-settings',
      ));
      
      acf_add_options_sub_page(array(
          'page_title'    =&gt; 'Theme Footer Settings',
          'menu_title'    =&gt; 'Footer',
          'parent_slug'   =&gt; 'theme-general-settings',
      ));
      
  }
  </code></pre>
  <hr>
  <h2>What i tried</h2>
  <pre><code>add_action( 'admin_menu', 'main_home' );
  
  /**
   * Adds a submenu page under a custom post type parent.
   */
  function main_home() {
      add_submenu_page(
          'theme-general-settings',
          __( 'Books Shortcode Reference', 'textdomain' ),
          __( 'Shortcode Reference', 'textdomain' ),
          'manage_options',
          'books-shortcode-ref',
          'books_ref_page_callback'
      );
  }
   
  /**
   * Display callback for the submenu page.
   */
  function books_ref_page_callback() { 
      ?&gt;
      &lt;div class=&quot;wrap&quot;&gt;
          &lt;h1&gt;&lt;?php _e( 'Books Shortcode Reference', 'textdomain' ); ?&gt;&lt;/h1&gt;
          &lt;p&gt;&lt;?php _e( 'Helpful stuff here', 'textdomain' ); ?&gt;&lt;/p&gt;
      &lt;/div&gt;
      &lt;?php
  }
  </code></pre>
  <p>Result
  It does not work :  url becomes like :  website.com/wp-admin/books-shortcode-ref</p>
  <p>If I change books-shortcode-ref to theme-general-settings it works but the it becomes same as what acf plugin used to go.. I have to add options using acf fields.</p>