Structure: Item returned no child

Studio logs Pane resolution error at index <n>: Pane returned no child in the browser console when you open a list item that doesn't resolve to a child pane. In most cases, you want to return a child when a list item is clicked. If you are receiving this warning, the list item probably doesn't define a child, or a custom child resolver returns undefined.

You usually want to specify a child for an item:

S.listItem()
  .title('George R. R. Martin')
  .child(
    S.documentList()
      .title('GRRM books')
      .filter('_type == "book" && author._ref == "grrm"')
      .apiVersion('2026-10-01')
  )

If you pass a function to .child(), make sure it returns a pane for every ID it can receive. A resolver that returns undefined for some IDs logs the same warning. This resolver returns a document list for whichever author is clicked:

S.listItem()
  .title('Books by author')
  .child(
    S.documentTypeList('author')
      .title('Authors')
      .child((authorId) =>
        S.documentList()
          .title('Books')
          .filter('_type == "book" && author._ref == $authorId')
          .params({authorId})
          .apiVersion('2026-10-01'),
      ),
  )

Omitting .child(...) still logs Pane returned no child. There is no supported way to mark an item as an intentional leaf.