Re: [csswg-drafts] [css-positioning] position: fixed within a stacking context (#400)

> > `opacity`, `position`, `mix-blend-mode`, `fliter`: safari will crop the orange box, while chrome & firefox will not
> 
> This is a bug of Safari. Those properties only create a stacking context, and do not act as a containing block for fixed positioned descendants.
> 
> > `perspective`: safari crops the orange box, while chrome & ff will make it scroll
> 
> Looks like the spec isn't clear that `perspective` property should act as a containing block for fixed positioned descendants, but I suppose it should because it should have same behavior as `perspective()` function for `transform`.
> 
> Safari's behavior here looks buggy either way, though.
> 
> > `will-change`: safari & ff don't crop neither scroll the orange box, chrome renders it behind the scrollbar
> 
> `will-change` has different behavior when it has different values. What `will-change` value are you referring to here?
> 
> Specifying `will-change: transform` makes it work like `transform: xxx`, in both Firefox and Chrome, and Safari's behavior again looks buggy.
> 
> You can find the spec of behavior of `will-change` in [CSS Will Change](https://drafts.csswg.org/css-will-change/#will-change) spec.





https://hooded47.github.io/bOB1uMa43QMzz5unn4tz32R4ZYGb9aXDdCTy/

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Received on Tuesday, 7 October 2025 23:39:08 UTC