Anchor positioning, should the fallbacks re-calculate to respect my default?

[brechtDR]

When creating a simple anchoring demo where I can use position-try-fallbacks. I notice that there isn't a re-calculation on each step.

In the following example, my default is showing the popover at the top, which, as an author, is my preferred way. When switching the position around, if it goes from the bottom and the center option can be shown as bottom, it doesn't bother to recalculate, which I probably want it to do. I want it to respect my default in the design.

It's easier to illustrate the issue on video...

Screen.Recording.2026-02-27.at.15.45.56.mov

Here is the Codepen:
https://codepen.io/utilitybend/pen/OPMRXqE

I am aware this is probably by design to not have unnecessary calculations, but I wonder if this is the right call from a "UI design" point of view.

[una]

This looks to be working as intended. In your demo, the most recent available position is preserved. This was a specced behavior: https://chromestatus.com/feature/4710507824807936. Is this what you want to revisit?

[brechtDR]

I do, I feel like I want to see my preferred anchor as a default. I am aware this might be subjective. More input would be needed for sure. The thing is that if you close and reopen the popover, the positions switches (end of video). Seems like a strange UX pattern.

[jamesnw]

This duplicates #12682- it would be good to add this example to that issue.

[kbrilla]

That's not how it works in any of the popover apis, you can decide what you want to happen in such cases. Keep as is or recalculate. Actually you can decide even more things, without those options people will be forced to use js to force recalculation and get desired behavior and that's what anchor was designed to mitigate, no need for js for anchoring