Open Bug 1599989 Opened 2 years ago Updated 2 years ago

[ESR68] Visual glitches when hovering over Tab bar and URL bar after disabling hardware acceleration and setting to cairo


(Core :: Graphics, defect, P1)

68 Branch



Tracking Status
firefox-esr68 --- affected
firefox70 --- unaffected
firefox71 --- unaffected
firefox72 --- unaffected


(Reporter: atrif, Assigned: jrmuizel, NeedInfo)



(Keywords: regression)


(1 file)

Attached image hover_problem.gif

Affected versions

  • 68.3.0esr (20191126000427)

Affected platforms

  • Windows10 x64
  • Windows 7x64


  • Set layers.acceleration.disabled to true and to cairo in about:config and restart the browser.

Steps to reproduce

  1. Launch Firefox after meeting the preconditions and open multiple tabs.
  2. Hover over the URL bar and the Tab Bar.

Expected result

  • No visual glitches on the Tab Bar and URL bar.

Actual result

  • The position of the and the format of the text on the Tab Bar and URL bar is changed when hovering.

Regression Range

  • Reproducible with Firefox 61.0a1 (20180505220904). I will search for one ASAP.


  • Attached a screen recording with the issue.
  • The issue is happening on the right side of the mouse when hovering as seen in the screen recording.
  • Not reproducible on Firefox 72.0a1(20191127215655) and Firefox 71.0 (20191125204040).
Has Regression Range: --- → no
Has STR: --- → yes

(from bug 1559810 comment 9)

Pushed by
disallow Cairo as content/canvas backend. r=jrmuizel

Wontfix or not? ESR 68 is supported until Q3/2020. Should bug 1559810 be uplifted?

Flags: needinfo?(lsalzman)

Jeff, should we uplift the patch to disable Cairo for ESR? Currently using Cairo is as a render backend is deprecated in ESR, but we didn't remove it from there.

It's not really a priority to investigate/fix this, I think, so we can either WONTFIX, or uplift the disable Cairo patch. However, certain people might still be relying on ESR to support Cairo for a little while a longer, so I am not sure we want to remove that escape hatch for people who for whatever reason still want to use it.

Flags: needinfo?(lsalzman) → needinfo?(jmuizelaar)

Marking as high-priority to make a decision on what to do.

Assignee: nobody → jmuizelaar
Priority: -- → P1
See Also: → 1528244

Hello! Attaching the regression range here:
Last good revision: f63559d7e6a570e4e73ba367964099394248e18d (2017-11-08)
First bad revision: 41a66272bd113526fa1e533268ebd5bbf39f7532 (2017-11-09)

Has Regression Range: no → yes
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