[Bug 2129765] Re: Kubuntu 25.10: Clicking on "Software Sources" within Discovery, doesn't launch ubuntu's software-properties

[Rodrigo Lledó]

Running pkexec software-properties-qt manually from a terminal produces
the following error:

====
qt.qpa.xcb: could not connect to display
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: minimalegl, wayland, vkkhrdisplay,
eglfs, offscreen, wayland-egl, vnc, minimal, linuxfb, xcb.

Aborted (core dumped)
====

libxcb-cursor0 is installed and up to date. The issue does not occur under X11, where both Discovery and software-properties-qt work correctly.
It seems related to how pkexec launches Qt apps under Wayland.

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https://bugs.launchpad.net/bugs/2129765

Title:
  Kubuntu 25.10: Clicking on "Software Sources" within Discovery,
  doesn't launch ubuntu's software-properties

Status in software-properties package in Ubuntu:
  Confirmed

Bug description:
  I'm on Kubuntu 25.10, but this bug was there even in 25.04

  Whenever I click on "Software Sources" within KDE Plasma's Discovery,
  it won't launch (k)ubuntu's software-properties, making ppa handling,
  or switching release upgrade methods (lts or normal) impossible from
  the GUI.

  The only workaround as far is launching via:
  sudo software-properties-qt

  Important note. While you can see I have backport ppa enabled for
  kubuntu, this bug happened right after a fresh installation before
  backports were enabled. This is a known bug, many people on reddit
  experience the same bug lately.

  ProblemType: Bug
  DistroRelease: Ubuntu 25.10
  Package: software-properties-qt 0.114
  ProcVersionSignature: Ubuntu 6.17.0-5.5-generic 6.17.0-rc7
  Uname: Linux 6.17.0-5-generic x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.33.1-0ubuntu3
  Architecture: amd64
  CasperMD5CheckResult: unknown
  CurrentDesktop: KDE
  Date: Fri Oct 24 17:04:30 2025
  InstallationDate: Installed on 2025-10-23 (1 days ago)
  InstallationMedia: Kubuntu 25.10 "Questing Quokka" - Release amd64 (20251007)
  PackageArchitecture: all
  SourcePackage: software-properties
  UpgradeStatus: No upgrade log present (probably fresh install)

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