"children_of" produces flat output?

I’m using the following shortcode:

[custom_menu_wizard menu=main children_of='example-0']

It produces the following output:

<ul id="menu-example-0" class="top-menu">
     <li id="menu-item-20" class="menu-item menu-item-type-post_type menu-item-object-page current-page-ancestor current-page-parent menu-item-20">
          <a href="[URL]">Example 1</a>
     </li>
     <li id="menu-item-21" class="menu-item menu-item-type-post_type menu-item-object-page current-menu-item page_item page-item-16 current_page_item menu-item-21">
          <a href="[URL]">Example 2</a>
     </li>
</ul>

So, basically, it outputs:
– Example 1
– Example 2

Problem is, Example 2 is a subitem of Example 1. Is there a way to retain submenu structure when filtering using children_of?

https://www.ads-software.com/plugins/custom-menu-wizard/