[csswg-drafts] [css-anchor-position-1] Compensating for Scroll & `overflow: clip` in one axis (#12842)

dshin-moz has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-anchor-position-1] Compensating for Scroll & `overflow: clip` in one axis ==
Currently, we [compensate for scroll](https://drafts.csswg.org/css-anchor-position-1/#compensate-for-scroll) if `anchor()` refers a default anchor, or an anchor that has the same scroll container.

However, if we have e.g.

```
<div class=scroller>
  <div class=default-anchor style="anchor-name: --default;"></div>
  <div class=another-scroller style="overflow-x: scroll; overflow-y: clip;">
    <div class=another-anchor style="anchor-name: --another;"></div>
  </div>
  <div class=positioned>
</div>
```

and `.positioned` has `position-anchor: --default; top: anchor(--another, bottom);`, no scroll compensation is currently done in that axis, I imagine because `overflow-x: scroll` makes `.another-scroller` [a scroll container](https://drafts.csswg.org/css-overflow/#propdef-overflow).

Still, seems a bit odd that we won't compensate for scroll, even if `--default` and `--anchor` would scroll together?

(Testcase attached)
[anchor-scroll.html](https://github.com/user-attachments/files/22473066/anchor-scroll.html)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12842 using your GitHub account


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Received on Monday, 22 September 2025 17:41:08 UTC