Compiz ‘Thumbnail Window Previews’ artefacts (further fix +)

Bug #1606369 reported by David Black on 2016-07-25
This bug affects 3 people
Affects Status Importance Assigned to Milestone
compiz (Ubuntu)
Martin Wimpress
Nominated for Xenial by Martin Wimpress
Declined for Yakkety by Brian Murray

Bug Description

With current settings, Galculator creates an unsightly additive thumbnail artefact which remains after thumbnail preview closes (screen capture link).

[Test case]
1. Open GCalculator
2. Verify no artifacts are done

[Possible regressions]
Shadows might be not visible

# Fix

- active-shadow-x-offset 6
+ active-shadow-x-offset 2

- active-shadow-y-offset 6
+ active-shadow-y-offset 2

- inactive-shadow-x-offset 6
+ inactive-shadow-x-offset 2

- inactive-shadow-y-offset 6
+ inactive-shadow-y-offset 2

# This fix also benefits all Compiz windows, as shadows become more proportionally balanced.


# Recommendation
With current settings, thumbnails occupy almost half the screen vertically on a Netbook (1024x600 resolution).

# Fix

- thumb-size 280
+ thumb-size 256


Edit: Simplified bug report/fix, tried to improved readability. Thanks

Related branches

David Black (db4tech) on 2016-07-25
description: updated
description: updated
description: updated
Changed in compiz (Ubuntu):
milestone: none → xenial-updates
importance: Undecided → Low
assignee: nobody → Martin Wimpress (flexiondotorg)
status: New → Triaged
Changed in ubuntu-mate:
status: New → Triaged
importance: Undecided → Low
Changed in compiz (Ubuntu):
milestone: xenial-updates → none
David Black (db4tech) on 2016-10-14
description: updated
David Black (db4tech) on 2016-10-14
description: updated
Csaba Nemethi (csaba-nemethi) wrote :

The solution proposed by David Black won't eliminate all artefacts related to the thumbnail window previews. To see this, apply the proposed solution and then just type "wish" in a MATE-Terminal. The resulting window has a geometry of 200x200, and the corresponding thumbnail still gives rise to the reported artefact. Same problem with any other top-level window having a sufficiently small size.

Alternative solution: Change org.compiz.profiles.mate.plugins.thumbnail.border from the value 12 to 19 (or higher).

With this patch, I could no longer reproduce that annoying thumbnail artefact, regardless of whether the change proposed by David Black was in effect or not.

BTW: IMHO, the shadow effect generated by the original offset value of 6 (for active-shadow-x-offset, active-shadow-y-offset, inactive-shadow-x-offset and inactive-shadow-y-offset) looks better than the one corresponding to the proposed offset value of 2). Of course, this is just matter of taste.

Csaba Nemethi (csaba-nemethi) wrote :

After some more testing I came to the conclusion that proportionally balanced shadows (as proposed by David Black) will result in improved appearance when using a light theme (and will be OK for dark themes, too). Also, with that fix in effect, it is sufficient to change the value of org.compiz.profiles.mate.plugins.thumbnail.border from 12 to 15 (instead of 19) in order to completely eliminate the reported artefact. Consequently:

Alternative solution revisited: Apply the fix proposed by David Black AND change the value of org.compiz.profiles.mate.plugins.thumbnail.border from 12 to 15.

Changed in compiz (Ubuntu):
status: Triaged → In Progress
status: In Progress → Fix Committed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package compiz - 1:

compiz (1: artful; urgency=medium

  [ Martin Wimpress ]
  * mate: Avoid artefacts of Windows Thumbnail Previews (LP: #1606369)

 -- Marco Trevisan (Treviño) <> Mon, 15 May 2017 05:51:32 +0000

Changed in compiz (Ubuntu):
status: Fix Committed → Fix Released
Changed in ubuntu-mate:
status: Triaged → Invalid
description: updated

Hello David, or anyone else affected,

Accepted compiz into xenial-proposed. The package will build now and be available at in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at . Thank you in advance!

Changed in compiz (Ubuntu Xenial):
status: New → Fix Committed
tags: added: verification-needed verification-needed-xenial
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