17.10 - flickering overlay patterns in gnome-terminal

[Jonas Bojesen]

Clean install of Ubuntu 17.10.

For gnome-terminal select color-scheme "black on light yellow".

Overlay partly with e.g. Chrome (Browser) or Geany (editor). Then the border shadow of the e.g. Geany produces flickering extended shadows in the gnome-terminal. Foto with the extended shadows is attached.

This bug was introduced with 17.10. This flickering didn't appear in 17.04, 16.10, 16.04...

Working as a developer with several open terminal windows on the desktop, this produces a disturbing desktop environment and mitigated by covering not used terminal windows complete with other apps.

Haven't reproduced with other apps than gnome-terminal.

Hardware
Lenovo Thinkpad e330, cpu : Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
gpu Builtin : HD 4000

[Egmont Koblinger (egmont-gmail)]

I've tried multiple desktop environments (GNOME on Wayland / Xorg, Ubuntu on Wayland / Xorg, Unity 7 [Xorg only]), but couldn't reproduce your problem with a new user. However, I've seen screenshots similar to this IIRC in Red Hat's or SUSE's bugzilla.

Which desktop environment do you use? (The window decoration of gnome-terminal suggests "Ubuntu", although buttons aren't on the right.) Also, Wayland on Xorg? Can you try the other options and see if the bug is still present?

Did you migrate your user settings (e.g. keep your home directory) during the fresh install of 17.10, or is it a newly created user? Could you please create a brand new user and check the behavior?

By Chrome (Browser) do you mean chromium-browser as shipped by Ubuntu?

What's that slightly pink-ish rectangle at the bottom left of the screenshot? Is that another window? Is it only a mere coincidence that its bottom aligns with the shadow artifact in the terminal, or does that window peek through gnome-terminal?

Do you have transparency enabled in gnome-terminal (Profile preferences -> Colors)? If so, does disabling that help?

Does the problem also occur with other gnome-terminal color schemes (e.g. enable "Use colors from system theme")?

Thanks!

[Jonas Bojesen (jonboj)]

Thanks for the feedback. Have done some more tests.

* For a fresh new user the bug also occurs on a fresh installation of Ubuntu 17.10.

* The bug don't occur on the laptop monitor, only external monitor connected with HDMI cable.

* If the Gnome Terminal Profile - "Use transparency from system theme" is disabled the flickering don't occur.

* Actually not related to Chrome, could be reproduced with Geany (editor).

To me this solves the issue, so could be closed if the deselection of "Use transparency from system theme" don't have any significant side-effects.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dan Watkins (oddbloke)]

I can reproduce this on 17.10, but only on my external monitor.

[Tigran Aivazian (aivazian-tigran)]

I would like to mention that if you enable the option "Use transparency from system theme" then the flickering is even easier to reproduce just by typing SPACE in gnome-terminal --- you will that the cursor leaves a shadow/ghost behind itself which disappears after a couple of seconds. Also, executing "ls -l" (in a non-empty directory :) you will see that as the output scrolls up it leaves a shadow ghost which disappears only after a few seconds.

This was so EXTREMELY annoying (imagine editing source code in vim and going mad because of these shadow blocks of code :) that I even thought of reverting back to 16.04, but fortunately I found this bug report which provided the workaround to disable "Use transparency from system theme" which works fine. Thank you!

Oh and yes, this only happens on the second/external monitor connected via VGA.

Btw, there is another annoying bug here --- when the mouse is on some areas of the main monitor another duplicate mouse pointer is visible and moving around on the second monitor. My second monitor is in portrait, so this "extra" mouse pointer is moving in the perpendicular dimension which is distracting.... But I guess this belongs to a separate bug report.

[Todd Ross (brainsick)]

This is happening to me too. It's HUGELY distracting when trying to use 2, 3, or more terminal windows.

I have 3x U2711 monitors hooked up via display port to a R9 Fury, so hardware doesn't seem to be a commonality.

Thanks for the Gnome Profile Terminal transparency workaround.

[Daniel Boyd (danboyd)]

Can confirm this is happening for me as well.

Dell Precision 7510
NVidia GM107GLM [Quadro M1000M]
Ubuntu 17.10
NVidia proprietary driver 324.111

[Sangwook Kim (overfit)]

My machine has the same problem.

Ubuntu 18.04
NVidia GTX 1080
Dell U2718Q Monitor x 2, connected by Mini DP cable

[Jenna Nelson (jem)]

I'm affected by this bug. I independently discovered the disable "Use transparency from system theme" fix.

I don't think I had this problem with an NVIDIA graphics card, it was only when I changed over to an AMD RX580 that the flickering started.

Ubuntu 18.04
AMD RX580

[Fernando Barbosa (fer-one)]

I am affected too. And using Ubuntu 18.04 and a NVIDIA card.

[priv (privism)]

Also on Ubuntu 18.04 i7-4790 with Intel Integrated Graphic Card.

I think this is not related to graphic card.

If you still want to use transparency from system theme, you can try following:

1. Uncheck "Use transparency from system theme"
2. "Check Use tranparent background"
3. Re-check "Use transparency from system theme"

And the background will become stable with system theme transparency.

I guess gnome terminal sometimes mistakenly checking the grayed out "Use transparent background" setting and disabled transparency, thus cause the flickering.

[Christopher Snowhill (kode54)]

Confirming that this issue does occur with Ubuntu 18.04.1, i7 3770, with AMD Radeon RX 480, using AMDGPU. I'm also using the kernel ppa 4.17 from June 4th, so I can keep AMDGPU DC enabled and use my primary monitor's DVI-D dual link connection to support 120Hz refresh rate.

I can also confirm that unchecking "Use transparency from system theme", checking "Use transparent background", and re-checking "Use transparency from system theme", results in a stable background. Perhaps "Use transparent background" should check itself if the system theme employs transparency?