If I create the pages `w/haystack` and `w/haystack/needle`, both show up in my top level hierarchy as expected, and viewing `w/haystack` shows needle in it's hierarchy. Then I move `w/haystack` to `w/haybale`, but it does not move `needle` with it. Now when I go to the hierarchy at `w/` I see `haybale` only, and the hierarchy at `w/haybale` does not show needle either. Fortunately the direct URL to needle still works.
If I go to `w/haystack` it tells me the page has moved, and does show `needle` in it's hierarchy. If I edit and save this page (creating a new `w/haystack`) I can again see haystack and needle in the top-level hierarchy.
I do not think the descendants should be orphaned in the hierarchy when their ancestor is moved. Maybe this means moving the descendants automatically at the same time, or maybe auto-create a placeholder document to replace the moved document, or some other solution.