Thank you for the provided information. Please take a look at this documentation
explaining how group pages work and that the first child page is displayed after you click a group page. When recrating the menu you described I used horizontal navigation as I saw in your screenshots and "all pages under particular page" option selected and the particular page is the group page of those pages I want to display. Note the difference about child pages and sibling pages. Siblings are the pages that are placed at the same level like your Home, Who we are, our business model. And that is the case when you click the about us page it shows all pages on that level ( they are siblings).
Hope this helps and if you need further assistance please write back.
All the best,
the Telerik team
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