Sorry about that, I accidentally uploaded a version of the repro-case that had the background image removed. Here is the correct version that demonstrates the issue.

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Unable to reproduce the issue on mac 10.13.5 using chrome reported version #67.0.3396.87 and latest canary #69.0.3457.2.

Attached a screen cast for reference.

Following are the steps followed to reproduce the issue.
------------
1. Ensured "Show scroll bars" is set to "When scrolling" in System Preferences > General
2. Downloaded attached index.html and opened in Chrome.
3. Resized the browser so only 15 items are visible.
2. Scrolled list of items to bottom of list.
3. Did not observe any rendering artifact.

sgerace@ - Could you please check the issue on latest canary #69.0.3457.2 by creating a new profile without any apps and extensions and please let us know if the issue still persist or not.

Thanks...!!

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I was able to reproduce the issue with a fresh install of Chrome Canary (see attached video). In the video I played around with turning on and off the scroll bar settings, we well as deleting the icon in the DOM so you can see how both change the behavior. Interestingly, after I remove the icon from the DOM you can see the artifact appear for a split second while I'm scrolling, but then it goes away.

Also, unsurprisingly, when I disable hardware acceleration the problem goes away as well. Please let me know what else I can do to help diagnose the issue. I feel that I would have noticed this issue as soon as it started manifesting itself (since the problem occurs in an application we're working on), and it seems too coincidental that I noticed it right after the update to Chrome v67. Is it possible to revert to a previous version of Chrome (i.e., v66) to see if that narrows down the issue?

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It's been a few weeks and I was just wondering if there has been any progress towards reproducing this issue on your end. I'm consistently seeing the issue on our production site on my machine, so perhaps it is something specific to my hardware/software configuration? I'd be happy to provide any additional information that might aid in diagnosing the problem.

Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

So I just noticed that this is also affecting the developer tools (see attached screenshot). I'm beginning to wonder if there is something going on with my machine. Could it be possible that a Chrome software bug is causing all of this?

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However, I would add to my previous comment that I'm only seeing the issues in the developer tools when on a site that causes the issue. In other words, if I remove the icon in the repro case, it stops happening in the developer console too.

I can't reproduce on 69.0.3476.0 with or without retina.

@ccameron, anay ideas?

Please go to about:gpu, print as a PDF, and attach the PDF.

It looks to be either a GPU hardware bug (if it's just on one machine, that's very likely), or a driver bug. Do you have anything unique about your system (like a USB display, or something like that)?

As per comment#10 adding Needs-Feedback label and requesting reporter to respond back/provide the required info on C#10.

Thanks!

See attached gpu report.

As far as monitors, I have two external monitors plugged in, one running on Thunderbolt and one running on HDMI. I've tried both monitors in isolation (just the Thunderbolt and just the HDMI) and the problem still exists. That being said, as I originally mentioned, I don't see the issue when running exclusively through the laptop display (i.e., no external monitors). 

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Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Tried checking the issue on reported chrome version 67.0.3396.87 using MacBook Pro 10.13.5 and 10.13.1, we couldn't reproduce it from our end. As we do not have exact hardware setup mentioned in comment#12 to check and confirm the issue requesting someone from respective team to have a look into this and help in further triaging it.

Thanks!

As per comment #3 and #14, we are unable to reproduce the issue from TE-end. Hence, adding label TE-NeedsTriageHelp for further investigation from dev team.

Thanks...!!

Operating system Mac OS X 10.13.5
GPU0 VENDOR = 0x10de, DEVICE= 0x0fd5 *ACTIVE*
GPU1 VENDOR = 0x8086, DEVICE= 0x0166

This is the same machine that I'm using for development. I'll take a look after my 10.13.5 upgrade.

Interestingly, I found another site that exhibits the same problem on my machine. When I visit https://caolan.github.io/async/ and scroll the left sidebar (containing the various methods of the library, I see the exact same behavior as the repro-case.

@ccameron Any luck reproducing on your end?

Thanks!

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Assigning to ccameron to look at based on comment #16.

Not able to get this to reproduce on my machine. This is feeling that it may be specific to this particular machine.

I assume the issue goes away if you use the flag --disable-mac-overlays

Actually, @ccameron, adding the flag --disable-mac-overlays does not make the problem go away (I tested on both Chrome 70.0.3538.67 and Chrome Canary 72.0.3584.0). I'm assuming this is the proper way to apply run-time flags:

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --disable-mac-overlays

(as described in https://www.chromium.org/developers/how-tos/run-chromium-with-flags)

However, as I mentioned in comment #4, if I go to Chrome Settings > Advanced > System and disable "Use hardware acceleration when available" the problem DOES go away.

Yeah, hmm. Then something is is somewhere in compositing-land, or this may be a machine-idiosyncratic GPU-brokenness issue, not sure what the next steps are.

Is there anything I can do on my end to help diagnose? I'm actually seeing this quite frequently now on various websites (i.e., not just while working on our application) and it has become quite an annoyance. I'd be happy to hop on a web meeting so you can see the issue and interactively debug, if for no other reason than to determine if it is a symptom of early stage GPU failure. My only hesitation to label it a machine-specific issue that is that this is still only happening on Chrome, I've yet to see anything like this with any other browser (or application).

 Issue 900266  has been merged into this issue.

Updating the title.

Can you run with 
  --disable-mac-overlays --show-mac-overlay-borders
and show a screenshot of the distortion (I'm going to want to see the shape of the borders).

Also try running with'
  --disable-gpu-memory-buffer-compositor-resources --show-mac-overlay-borders
and see if the issue goes away.

Okay, so I just tried to run with
  --disable-mac-overlays --show-mac-overlay-borders
and I've attached the screenshots on both the repro-case and https://caolan.github.io/async/

I tried to grow/shrink the window so you could see it at different sizes (not sure that helps at all). I'm not sure what you mean by "the shape of the borders" since the only border I saw was the outer border of the browser. 

Also, I tried running with 
  --disable-gpu-memory-buffer-compositor-resources --show-mac-overlay-borders
and the issue was still there.

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One more idea ... does --disable-gpu-rasterization do anything?

Yep, that seemed to fix it. It also made the borders much more interesting, whatever that is worth ;-) (see attached screenshots).

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Marking available for GPU triage.

I have the exact same machine as this user and am not experiencing this bug, so I wouldn't want a GPU blacklist entry. But it does appear that there are GPU bugs here that are causing problems.

FYI you can disable GPU rasterization in about:flags (so you don't have to use the command line).

@ccameron, I'm curious, what kind of performance impact should I expect if I disable GPU rasterization? Is this something I can safely disable without a significant impact?

It won't make a difference for things like scrolling. For things like raster-based animation, it could be a bit more jerky. Nothing earth-shattering though.