See http://www.thepopgroup.net/. We and Safari checkerboard a *lot* on this page. Sometimes the paint doesn't happen for a few seconds, leading to the illusion that content disappears as you scroll. Chrome disables APZ on this patch and while their scrolling is janky it's a much better experience overall. Edge seems to have no problem painting this page fast with APZ.

That page almost seems to hang my content process. It looks like billions of facebook buttons are loading all the time. I think whatever happens here needs to be fixed at a different level than APZ.

It would be good to get a checkerboard report from about:checkerboard on a Retina macbook when this happens. Copy the raw log from the bottom of the page and attach it here.