Hello Martin Walker,
Thank you for posting in Q&A forum.
Microsoft removed this feature in the 23H2 update due to the new WinUI3-based header. And there is no official information about when they will add it back.
You could try to enable it manually by a GitHub project:
Reference:
https://winaero.com/windows-11-restores-file-drag-n-drop-onto-address-bar-in-file-explorer/
I hope the information above is helpful.
If you have any questions or concerns, please feel free to let us know.
Best Regards,
Daisy Zhou
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