@ Jonahtan, could this bug be a regression from the graphite2 update (bug 1191167)? STR: 1. Load https://medium.com/matter/the-web-we-have-to-save-2eb1fe15a426 2. Click any of the numbered "comment bubbles" on the right margin. RESULT: As the comments open, the page text is blurry and pixelated for a second. I bisected this regression to the following mozilla-central pushlog. (I can't narrow the regression further right now because mozregression is having trouble downloading mozilla-inbound builds.) https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=3f135a8ead22&tochange=8cba870a352c

@ Kats, this bug seems to be a regression from enabling APZ on OS X. Now that I have a better understanding of the STR, I bisected this bug again to this mozilla-inbound push implicating APZ bug 1157746: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=6ad92b48085b&tochange=cfc312d8ef20 STR: 1. Load https://medium.com/cuepoint/streaming-music-is-ripping-you-off-61dc501e7f94 2. Scroll down to the section entitled "The Flaw in the Big Pool". 3. Hover your mouse pointer of the section title. 4. Slowly move the mouse pointer vertically over the paragraphs below the section title. RESULT: The page text will blur and the line spacing will shift.

Hm, I'm not able to reproduce using either of the two STRs above. Does the text remain blurry, or does it clear eventually? Can you grab a screenshot before/after?

The page is only blurry for about 100 ms, too quickly to capture a screenshot. Both the page text and images blur. I can reproduce on two different MacBook Pros, both with the internal Retina display and a non-HiDPI external display.

Ok, thanks. I'll keep an eye out for other reports of this.