@jensimmons.bsky.social @saron.bsky.social @jondavis.bsky.social Sorry to chase, but any thoughts on what I could try next to help debug/prevent this, other than just remove content-visibility? Would it be worth raising a WebKit bug if I could make a repro? I can't reproduce it on macOS, only iOS

This all looks fantastic!

It seems to be the `content-visibility: auto;` that causes the issue, not the `contain-intrinsic-size`. I imagine there's something else on the page that combines with content-visibility to cause the issue, maybe our sticky header or something z-index or transform related?

I'm thinking maybe something compositing related but I'm a bit out of my depth! If you're based in the UK you can see a live example at shop.coop.co.uk?postcode=M60... – scroll to the bottom of the page then scroll back up to trigger the flicker.

Also, black tape pagination buttons, because why not?

Oooh, what would this be?

This is really relevant to me at work at the moment! @tammyeverts.com do you have a link to that Akami study on slowness leading to 28% abandonment, please? I'd like to quote it at work but with a direct link to the source.

urn:li:fs_relatablePostCommaBeenThere:ACoAABQ11fIBQLGQbB1V1XPBZJsRwfK5r1U2Rzt !

RSC

Totally, that's why I like the idea, after a salesperson explains how the 'script is async so there's no performance impact' then you can nod and let them put their money where their mouth (as long as the clause explains the testing methodology so it's harder to wiggle out of it later!)

Ahhhh that makes perfect sense! I was thinking of reviewing RUM data rather than synthetic/lab testing! Maybe add that to the post just in case other readers' minds go to the same place I did.

…I think the way to counter that would be to run a 50/50 A/B test to rule out any changes in demographics or any first-party code changes that could have introduced a performance regression