Open Bug 1494058 Opened 4 years ago Updated 2 years ago

Colored Artifacts Appear Above Tab Bar with OS X Mojave in Dark Mode


(Core :: Widget: Cocoa, defect, P2)

63 Branch




(Reporter: brandon.clinger, Unassigned)


(Blocks 1 open bug)



(1 file)

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:63.0) Gecko/20100101 Firefox/63.0
Build ID: 20180920135444

Steps to reproduce:

Enable OS X Dark Mode Theme. Enable Firefox Dark Theme. Browse the web with multiple tabs open.

Actual results:

A magenta, red and yellow artifact can be seen at the edge of the 'chrome' above the tab selection bar. It catches ones eye since it contrasts with the dark theme.

Unknown if this is an OS X issue, or a Firefox issue. The issue is also difficult in that I have not found a deterministic reproduction step sequence. Attempting to capture this with the built in screen recorder on OS X disrupted the dot flashing behavior. Instead see attached video screen capture from a phone.

Expected results:

No graphical anomalies or artifacts appear.
Summary: OS X Mojave Dark Mode Artifacts Appear → Colored Artifacts Appear Above Tab Bar with OS X Mojave in Dark Mode
Picture of the example artifacts that appear.
Video of the artifacts behavior.
Blocks: mojave
Component: Untriaged → Widget: Cocoa
Product: Firefox → Core
Are you still able to reproduce in the most recent Nightly?
Flags: needinfo?(brandon.clinger)
Priority: -- → P2
(In reply to Stephen A Pohl [:spohl] from comment #3)
> Are you still able to reproduce in the most recent Nightly?

I will begin this test - I will say after 20 minutes no sign. This is inconclusive. Any suspicion of a change affecting this?
Flags: needinfo?(brandon.clinger)
(In reply to Stephen A Pohl [:spohl] from comment #3)
> Are you still able to reproduce in the most recent Nightly?

This has occurred again with the latest nightly.
I and some other people have also been seeing this glitch, which is also sometimes grey or green.

I've managed to capture it on a screen recording:

Although browser-like applications like Firefox seem especially likely to trigger it, I've seen it in Firefox, Atom (Electron), Discord (Electron), and iTerm.

This leads me to believe the bug is likely in Apple's OS code, or it is somehow triggered by something these applications are doing.

Here's a Stack Exchange Q&A on the issue:
Oh one other thing. I was able to reproduce it in Light Mode, it just requires Firefox to still use a dark theme.
Some more information as I continue to better understand this glitch.

I've had pretty consistent success reproducing the bottom-edge version of this glitch using:

- Firefox Developer Edition (default dark theme)
- Developer tools panel open and docked to the bottom of the window (default dark dev tools theme)
- With the Console tab open or Split Console active (puts a nice dark area on the bottom of the window)
- Browsing to any website like
- Refreshing the page until it appears

Some other tidbits:

- It only seems to happen when the integrated graphics are in use. I've been unable to reproduce with the discrete card active.
- If I suspend the firefox and plugin-container processes over SSH while the glitch is happening using kill -SIGSTOP, the glitch continues flashing, indicating the glitch is outside the Firefox processes.
- Going further, I tried systematically suspending processes over SSH, to see which one might be responsible. The only one suspending causes the flashing to freeze with was WindowServer.
Duplicate of this bug: 1505373
Just to let everyone know, for reasons outlines in the linked Stack Exchange Q&A (in particular QuickTime can record it, but Digital Color Meter and Pixie cannot see it), I'm fairly certain this is actually an OS bug.

I filed a bug report with Apple on November 14th, but haven't heard anything back about it since.

If anyone has any pull with Apple, the Problem ID is: 46079638
At some point recently Apple marked my bug report as a duplicate of 45841204 so I guess they were already aware of the issue. It was not resolved in 10.14.2.

Is still still an issue in the latest version of 10.14?

Flags: needinfo?(alexanderomara)

Frustratingly, yes, it is still a problem in 10.14.3.

If anyone has any suggestions on how to motivate Apple to resolve the issue I would love to hear it.

The duplicate bug report I filed also suggests that the original bug is still open (although I'm not 100% sure it will update to reflect the original status).

Flags: needinfo?(alexanderomara)

I still see this periodically on both my Macs, one of them running 10.14.4.

Ever confirmed: true
Duplicate of this bug: redflash

Some new information:

It doesn't seem to happen nearly as often in the Firefox 70.0b12 (Developer Edition), and when it does happen I now have it happening on the top edge of the browser for me, rather than the bottom edge where it happens with Firefox 69.0.2.

The new macOS 10.15 Catalina is out, but I don't intend to upgrade to it right away. Can anyone confirm if it still happens in the new OS version?

Just updated to Catalina. Bug still apears randomly. I'm using dark mode and light firefox theme. When i try to take screenshot or resize window red dots disappears, seems like focus/refocus on the window make some redrawings.
FF 69.0.3 Mac OS 10.15 MacBook Air (Retina, 13-inch, 2018)

Reappears in v74.0

Same issue here on macos catalina and ff 72

Same issue here with mbp 15" 2019

(In reply to said from comment #21)

Same issue here with mbp 15" 2019

Catalina, FF 72, I noticed this mainly with the dark mode

See Also: → 1606840

Same issue with a MBP 16" and Firefox 77.0.1 in Dark Mode.

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