Various highly noticable graphical glitches have all started happening in Kinetic at the same time

[Aaron Rainbolt]

Filing this against the meta since the exact location of this bug currently isn't known (I highly suspect it's in Qt, though). While there are multiple issues involved here, they all started happening at the same time and so I suspect they're all the same bug, thus why they're all reported in the same bug.

Steps to reproduce issue 1:
1: Boot the latest Lubuntu Kinetic ISO.
2: Open Featherpad.
3: Click "File".

Expected result: The word "File" should still be visible, and the File menu should open.
Actual result: While the File menu does open, the word "File" vanishes. It reappears if you click somewhere else so that the File menu disappears.

Steps to reproduce issue 2:
1: Right-click on the desktop.
2: Hover over any of the items in the context menu that appears.

Expected result: A blue highlight should appear over any context menu that the mouse passes over.
Actual result: No highlight appears.

Other info:

This appears to have started happening after a Qt upload, so I highly suspect this is Qt related.

ProblemType: Bug
DistroRelease: Ubuntu 22.10
Package: lubuntu-desktop 22.10.3
ProcVersionSignature: Ubuntu 5.19.0-18.18-generic 5.19.7
Uname: Linux 5.19.0-18-generic x86_64
ApportVersion: 2.23.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: LXQt
Date: Fri Oct 7 13:09:11 2022
InstallationDate: Installed on 2022-10-07 (0 days ago)
InstallationMedia: Lubuntu 22.10 "Kinetic Kudu" - Daily amd64 (20221006)
SourcePackage: lubuntu-meta
UpgradeStatus: No upgrade log present (probably fresh install)

[Aaron Rainbolt (arraybolt3)]

Changing the Qt style from Breeze to Fusion makes things work as expected (though it changes the UI in a way that I, personally, dislike).

[Aaron Rainbolt (arraybolt3)]

The problem is the lack of blue highlighting. When you click on a menu item in a system with the Breeze theme, the text turns white, while the background turns blue. Since the blue highlighting isn't appearing anymore, the text appears to (mostly) vanish (really it turns white on a slightly off-white background). That same highlighting is missing when hovering over menu items.

[Aaron Rainbolt (arraybolt3)]

This bug doesn't seem to affect Kubuntu, so I'm not sure what exactly is wrong with Breeze + LXQt. It appears that Breeze and LXQt don't always work so well together from other discussions, so I'm changing this to a bug in lubuntu-default-settings so that a quick patch to change the default theme can fix it.

[Simon Quigley (tsimonq2)]

From the Lubuntu Release Management perspective, I'm unhappy with changing the default Qt widget style close to two weeks before the release. This is inconsistent with the idea of a User Interface Freeze. I'm -1 on the approach taken here, and would like to see an attempt made at diagnosing Breeze before I sponsor a patch related to this bug.

[Aaron Rainbolt (arraybolt3)]

Further research on this bug has confirmed that it is indeed a problem introduced in a recent change in Breeze. I intend on git bisecting this today (Central Daylight Time) and hopefully having a fix or at least a pinpointed commit by tonight or tomorrow.

[Rik Mills (rikmills)]

Actually the trigger is not in Breeze, but a change in kconfigwidgets 5.98.0. It just happened that doing test upgrades of Breeze also pulled in the 5.98.0 kconfigwidgets packages.

The commit that seems to be the issue is: https://invent.kde.org/frameworks/kconfigwidgets/-/commit/8c078b50fc867df0396c7cf76ff000a747de1043

It does seem to be a reasonable change from KDE, so unclear whether this should be a KDE bug, or if it should really be a lxqt issue where lxqt mishandles such changes. KDE does not have an issue with the change, only lxqt does.

[Rik Mills (rikmills)]

package with a possible upstream fix in: https://launchpad.net/~rikmills/+archive/ubuntu/bug1992196

[Launchpad Janitor (janitor)]

This bug was fixed in the package kconfigwidgets - 5.98.0-0ubuntu2

---------------
kconfigwidgets (5.98.0-0ubuntu2) kinetic; urgency=medium

  * Add upstream patch to fix lxqt Breeze colours (LP: #1992196)
    + d/p/upstream_intialize-default-decoration-colors.patch

 -- Rik Mills <email address hidden> Wed, 12 Oct 2022 14:01:38 +0100