krita: Adding a swatch group breaks the palette docker (Krita 6.0.0)

Nixpkgs version

• Unstable (26.05)

Describe the bug

On Krita 6.0, when I add a new swatch group to a palette, the docker stops rendering until I (a) switch to another palette and (b) restart Krita

This is present on the nixpkgs build of Krita 6.0, but not on the official AppImage build of 6.0 (which uses Qt 6.8 rather than 6.10 in the nixpkgs build - probably other differences too)

I'm using krita from nixpkgs-unstable but my system is mostly nixos 25.11

Full symptoms:

• The docker stops rendering the current palette (sometimes inconsistent - I've also experienced where it renders the first row of the current palette and no more)
• Switching to other palettes no longer renders the switched-to palettes
• Restarting Krita does not help
• The only way to fix it is to deleted the palette with the swatch group, select a new palette (which you still can't see), then restart Krita

Steps to reproduce

1. (Optional) Create a New Palette
2. Click "Edit New Palette"
3. Click "Add a Swatch Group"
4. Click "Ok"

Expected behaviour

A new heading and swatch group is added to the palette in the docker

Screenshots

What the palette looks like working before adding a swatch group

Palette broken after the swatch group is added

Even the default palette is broken:

What the palette looks like on the AppImage build:

Relevant log output

These are the logs, but they don't seem to indicate anything useful:

SESSION: 20 Apr 2026 22:07:15 +0100. Executing /etc/profiles/per-user/tony/bin/krita

Krita Version: 6.0.0, Qt version compiled: 6.10.2, loaded: 6.10.2. Process ID: 65480
-- -- -- -- -- -- -- --
20 Apr 2026 22:07:15 +0100: Style: breeze. Available styles: Breeze, Windows, Fusion
20 Apr 2026 22:07:16 +0100: Database is up to date. Version: 0.0.18, created by Krita 6.0.0, at Fri Apr 3 22:20:45 2026
20 Apr 2026 22:07:16 +0100: INFO: detected unstable build of Krita, foreign_keys constraint will be enabled
20 Apr 2026 22:07:16 +0100: INFO: switch foreign_keys state: 0 -> 1
20 Apr 2026 22:07:16 +0100: SAFE ASSERT (krita): "result" in file /build/krita-6.0.0/libs/resources/KisResourceCacheDb.cpp, line 2160
20 Apr 2026 22:07:17 +0100: Audio Playback Engine: KisPlaybackEngineQT
20 Apr 2026 22:07:19 +0100: Importing application/x-krita to application/x-krita. Location: /home/tony/Pictures/test.kra. Real location: /home/tony/Pictures/test.kra. Batchmode: 0
20 Apr 2026 22:07:20 +0100: Loaded image from application/x-krita. Size: 2048 * 2048 pixels, 4.16667 dpi. Color model: 8-bit integer/channel RGB/Alpha (sRGB-elle-V2-srgbtrc.icc). Layers: 28

Additional context

Reported to Krita team here: https://bugs.kde.org/show_bug.cgi?id=519191

But since it works on the AppImage, assumed to be a distro bug

System metadata

• system: "x86_64-linux"
• host os: Linux 6.19.12, NixOS, 25.11 (Xantusia), 25.11.20260413.7e495b7
• multi-user?: yes
• sandbox: yes
• version: nix-env (Lix, like Nix) 2.93.3 System type: x86_64-linux Additional system types: aarch64-linux, i686-linux Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /home/tony/.config/nix/nix.conf:/nix/store/vrfi5n3hma1x09hn4sasv6j4738z8ab7-plasma-workspace-6.5.6/etc/xdg/nix/nix.conf:/nix/store/6clc7pl6b3l4d5smwx4bkwnp59s9zx05-kglobalacceld-6.5.6/etc/xdg/nix/nix.conf:/nix/store/1aqmfdh493dgvsy9h37kph1giir8vmq8-baloo-6.20.0/etc/xdg/nix/nix.conf:/home/tony/.config/kdedefaults/nix/nix.conf:/nix/store/vrfi5n3hma1x09hn4sasv6j4738z8ab7-plasma-workspace-6.5.6/etc/xdg/nix/nix.conf:/nix/store/6clc7pl6b3l4d5smwx4bkwnp59s9zx05-kglobalacceld-6.5.6/etc/xdg/nix/nix.conf:/nix/store/1aqmfdh493dgvsy9h37kph1giir8vmq8-baloo-6.20.0/etc/xdg/nix/nix.conf:/home/tony/.config/kdedefaults/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/tony/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/tony/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/tony/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/gdxrycycvhnhgg13rqmhmcfv16bbl7s0-lix-2.93.3/share
• nixpkgs: /etc/channels/nixpkgs

Notify maintainers

@sifmelcara

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The report points to Krita 6.0.0, Qt 6.10.2, and libs/resources/KisResourceCacheDb.cpp:2160 in the build log; it also links KDE bug 519191. Start by comparing the Nixpkgs build with the working AppImage and reading that upstream report. Done means identifying whether the packaging difference causes the swatch-group reproduction and recording or implementing the appropriate fix.