When setting nagivation groups for standard pages in front matter the dropdown subdirectory setting is required

[caendesilva]

Using the following in _pages/page.md

---
navigation.group: My Group
---

Has no effect unless the following is set in config/hyde.php

'navigation' => [
    'subdirectories' => 'dropdown',
]

This feels wrong, since this does not necessarily mean the user wants to use subdirectories.