Re: [csswg-drafts] [css-anchor-position] Invalidation of last successful position option in cases not in the spec (#12577)

This [WPT test](https://github.com/web-platform-tests/wpt/blob/47beb4bcd05d135e935c871f8555b4901c38b783/css/css-anchor-position/position-try-switch-from-fixed-anchor.html) (`css/css-anchor-position/position-try-switch-from-fixed-anchor.html`) seems to imply that changing `display` to `none` should also invalidate the last successful position option

```html
<script>
waitForAtLeastOneFrame().then(() => {
  window.scrollTo(250, 100);
  // The initial option no longer fits. Switch to fallback.
  waitForAtLeastOneFrame().then(() => {
    window.scrollTo(0, 0);

    // The initial option would fit again, but so does the fallback. Redisplay
    // to move away from the fallback option.
    anchored.style.display = "none";
    waitForAtLeastOneFrame().then(() => {
      anchored.style.display = "block";
      takeScreenshot();
    });
  });
});
</script>
```

This sounds like Chrome saving the last successful position option in the element style, or some sort of data structure that goes away on `display: none`, so when `display` is changed to something else, the last successful position option isn't there anymore. Maybe we should amend the resolution to include `display`?

-- 
GitHub Notification of comment by tuankiet65
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12577#issuecomment-3234577050 using your GitHub account


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

Received on Thursday, 28 August 2025 18:47:27 UTC