As reported here https://bugzilla.mozilla.org/show_bug.cgi?id=1456514 and tested with the latest Servo nightly on Linux. I'm seeing a blue vertical line on:
https://github.com/servo/webrender

https://github.com/servo/webrender/issues/2706

https://twitter.com/firefoxnightly

I assume it is some kind of driver issue, as starting Firefox or Servo with LIBGL_ALWAYS_SOFTWARE=true "solve" the issue.
$ glxinfo | grep OpenGL
OpenGL vendor string: X.Org
OpenGL renderer string: AMD SUMO (DRM 2.50.0 / 4.16.4-1-ARCH, LLVM 6.0.0)
OpenGL core profile version string: 3.3 (Core Profile) Mesa 18.0.2
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 18.0.2
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.1 Mesa 18.0.2
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.10
OpenGL ES profile extensions:
After a bit of trail and error I ended up with the following small HTML file, which cause the issue on my system (tested with latest Servo nightly).
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<style>
blockquote {
border-left: 10px solid white;
}
</style>
</head>
<body>
<blockquote>
foo
</blockquote>
</body>
</html>

Can't repro with either Firefox or Servo at revision 7af725bff0faacadb6f6e4ff4a88157d8fed0562 on Linux/Intel GPU 520.
Would be great to have a capture taken from this (Ctrl+Shift+3, see https://github.com/servo/servo/pull/20315)
Would be great to have a capture taken from this (Ctrl+Shift+3, see servo/servo#20315)
Nothing happens if I press Ctrl+Shift+3, but taking a screenshot in Firefox with Firefox screenshot I get the expected result:

Would be great to have a capture taken from this (Ctrl+Shift+3, see servo/servo#20315)
Currently broken on Linux/win per: https://github.com/servo/servo/issues/20746#issuecomment-389300407
The blue left border just recently changed to pink for me on latest Nightly with Radeon HD after the webrender update (Bug 1461342).
Test case:
https://bugzilla.mozilla.org/attachment.cgi?id=8975316
Capture:
https://we.tl/7JC7Ju4Xcx
The blue left border just recently changed to pink for me on latest Nightly with Radeon HD after the webrender update (Bug 1461342).
I can confirm that.
This is fixed for me on latest Nightly since Bug 1463416 landed.
@klausenbusk could you check if it's fixed for you as well?
@klausenbusk could you check if it's fixed for you as well?
I can confirm that issue is fixed in Nightly but I still see the issue in the latest servo nightly.
I guess Servo nightly is not updating the WR dependency as often.
Updating WR in Servo is currently blocked on a rustc compiler bug :tada:
There's a pending WR update PR for Servo here https://github.com/servo/servo/pull/20892.
I'll close this for now, since it appears to be fixed in WR. Please feel free to re-open if you see again.
Most helpful comment
This is fixed for me on latest Nightly since Bug 1463416 landed.