Nicolás Peña Moreno

Yea I think we agree on counting partially onscreen movement. What I previously suggested was ignoring fully offscreen movement (with that being the starting or ending state), but you pointed...

Ok, that makes sense to me. I thought about it and excluding some offscreen cases has some problems in terms of the 'smoothness' of the layout shift function, so probably...

If I understand the concern correctly, here is the problem. Suppose I have a div with width and height 100 and it's offscreen and moving it onscreen to the top...

I would be fine excluding those, personally. Note sure how @skobes feels about this though

Are these cases covered by these changes? https://chromium.googlesource.com/chromium/src/+/main/docs/speed/metrics_changelog/2020_11_cls.md If so then the implementation has excluded these for a while but I don't think we updated the spec.

I think the Note in PerformanceTimeline should instead point to https://w3c.github.io/timing-entrytypes-registry/#registry. You can see there the size is 150. I do understand the concern about computing the data, so we...

> Any small-but-measurable duration would end up feeling like a kinda silly price to be paying, for no benefit, for sites that don't use the feature. Especially if we come...

No worries, let us know if there are wording suggestions you have to make this clearer (or happy to review a PR too).

Yea, that makes sense to me. Let's keep this issue open till such clarification is added.

I see, that's a valid concern. I can think of several mitigations to this if it turns out Mozilla cannot implement this in a performant way: 1. Reduce the buffer...