Emilio Cobos Álvarez

I think I agree with you in your test-case, but also that test case is not the most useful thing to look at, because the fallback to the initial value...

You _need_ to inherit the properties from outside, otherwise you get really unintuitive behavior with slotted contents even when there's no conflicts.

> So to be clear, this does not happen without the new Image().src assignment? That does seem strangely side-effecting. Correct, and agreed.

Chrome and Safari have even worse bugs here, see: https://issues.chromium.org/issues/375209498

FWIW I wrote a test for this: https://wpt.fyi/results/html/semantics/embedded-content/the-img-element/update-the-image-data/lazy-out-of-band-load.html Extra Safari issue: https://wpt.fyi/results/html/semantics/embedded-content/the-img-element/update-the-image-data/src-then-lazy-load.html

Why is this a media feature out of curiosity? Feels rather odd, is there any precedent for these `can-*`?

`mozilla::SmallPointerArray` is already opaque [here](https://searchfox.org/mozilla-central/rev/d1fbe983fb7720f0a4aca0e748817af11c1a374e/layout/style/ServoBindings.toml#303). If you add `mozilla::SmallPointerArray_Element` (or `mozilla::SmallPointerArray::Element`, forget which one is the right syntax) there, does it work? This is probably worth tracking upstream in https://bugzilla.mozilla.org...

I'm starting to get a bit concerned about the overhead of building all this info for callbacks unconditionally, but we could optimize in the future by allowing callbacks to opt...

@rwlbuis do you know what WebKit is doing here?

@nt1m so webkit parents all top layer elements (abspos and fixed pos) to the viewport rather than the root scroller? Isn't that incorrect?