STR) 1) go to http://news.google.com/ 2) scroll down a few swipes 3) scroll up a few swipes At some point, scrolling will get stuck. I can't go up or down, but a side-swipe will navigate to a different section.

What version of Fennec are you using? I'm not able to repro on Nightly.

Hey Kats, I was testing on 48 on a Galaxy S6. And yeah, it doesn't repro in Nightly (should have checked there too...), but the scroll lags pretty badly.

Ok, I can repro on 48, but not on 49 (Aurora Aug 1 build) or 51 (Aug 03 build). So it seems to only affect 48? And as that's on release already it's unlikely we'll fix it unless we do a dot release. Also problematic is that the site is managing all the scrolling itself - it's not APZ scrolling but JS scrolling. So even if there's something we're doing that's wrong it's not going to be easy to track down. I don't think there's anything actionable here so closing WFM but feel free to reopen if you disagree.

NO, I think that's the right resolution. I just tested with layout.css.prefixes.webkit=false and the problem as reported reproduces in Nightly... but that layout.css.prefixes.webkit=true will ride the trains in 49. If I had to guess, it would be a missing `webkitTransitionEnd` event.

> will ride the trains in 49 s/ride the trains/hit release/

(ugh, wrong field)

Im getting two different versions of the site on Beta vs Nightly 51 On Nightly i get the carousel version & AMP enabled news results with the problematic scrolling The site which i get on Beta doesn't seems to have the content when a side swipe is done but side swipe reveals more contentt on the Nightly version of the site also layout.css.prefixes.webkit=true - on nightly 51 as default Another issue is click change edition on nightly via google news hamburger button. There is no popup to select different countries, im stuck. Only "close" button works. Just curious even if its JS scrolling why does it have to be soo bad?

I'm not sure there is much that can be done here. It looks like Google may be A/B test this. :snorp and I got different pages. On my device scrolling was clearing being done with JS while on his device it was using APZ. I was able to change editions. It appears that the js maybe running very slowly as it took several taps to get the edition selection pop-up to show.

(In reply to Randall Barker [:rbarker] from comment #8) > I'm not sure there is much that can be done here. It looks like Google may > be A/B test this. :snorp and I got different pages. On my device scrolling > was clearing being done with JS while on his device it was using APZ. I was > able to change editions. It appears that the js maybe running very slowly as > it took several taps to get the edition selection pop-up to show. yup! the change edition started working after yesterday's build on the AMP enabled version; maybe due to this Bug 1290823 For fun i spoofed the Firefox android UA on the desktop Nightly and the site is un-scrollable Cant a testcase site with a JS scroll implementation be used and probably we can compare performance over other browsers and develop over it? Dont know if it will help but searching the internet i stumbled on this - https://developers.google.com/web/updates/2016/06/passive-event-listeners?hl=en

The version sent to Chrome UA on Gecko is working (and has a different layout, which is less fancy) In https://cdn.ampproject.org/viewer/google/v5.js There is a lot of code related to scrolling and touch.

If changing the UA works, this may be a good candidate for an override.

This issue was about the scrolling. The scrolling in my latest tests seems fine. I seem also to receive the same version on all browsers. The design on the left posted by bull500 https://bug1291444.bmoattachments.org/attachment.cgi?id=8777866 seems to be a kind of A/B testing with AMP news, but I can't reproduce.

(In reply to Karl Dubost :karlcow from comment #12) > This issue was about the scrolling. The scrolling in my latest tests seems > fine. > I seem also to receive the same version on all browsers. > > The design on the left posted by bull500 > https://bug1291444.bmoattachments.org/attachment.cgi?id=8777866 > > seems to be a kind of A/B testing with AMP news, but I can't reproduce. The video shows the problem First is chrome, next is Nightly and final is Nightly with a spoofed UA. Its a different site for Firefox UA even though its the same URL

Thanks bull500. So definitely we do not receive the same version (even when I explicitly put the Indian version). I'm receiving the same version than Chrome. And the scroll is blazing fast. There is also no other pages when sliding on the right side. :/

My guess is they are sniffing the location of the user and the forwarding the content specific to google India's or other region specific google sites; with no escape other than spoofing UA. Even if i change to the US edition it still serves me the problematic site(scrolling to the right side one).

Re-triaging per https://bugzilla.mozilla.org/show_bug.cgi?id=1473195 Needinfo :susheel if you think this bug should be re-triaged.

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