Re: [csswg-drafts] [css-anchor-position-1] Back-compat of scrollable containing block for all abspos with implicit anchors (#13067)

Additional points: 

> 1) As anchor functions are resolved at computed value time, you've "lost" if there was an anchor function even there.

This point is also an issue for the proposed solution of adjusting the `auto` inset. E.g. if just using the computed style, you need to capture that an inset was resolved by an `anchor()` function at CVT.

Another issue with adjusting the `auto` inset is that its confusing if the developer *does* set the other inset. For example:
```
<!DOCTYPE html>
<div style="position: relative; width: 100px; height: 100px; overflow: scroll;">
  <div style="width: 200px; height: 200px;">
    <div style="margin-left: 20px; margin-top: 20px; width: 50px; height: 50px; background: hotpink; anchor-name: --a;">
      anchor
    </div>
    <div style="position: absolute; position-anchor: --a; left: anchor(right); top: anchor(top); background: lime;">
       text text text text text
    </div>
  </div>
</div>
<!-- https://www.software.hixie.ch/utilities/js/live-dom-viewer/?saved=14299 -->
```

Then lets say the web-developer "oh I want to leave space of `10px` on the right" and sets `right: 10px` this radically changes the layout.


-- 
GitHub Notification of comment by bfgeek
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13067#issuecomment-3498601736 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Thursday, 6 November 2025 17:48:19 UTC