Dolphin (flatpak) → Windows 11 Dark Theme

Verified on Fedora 44 + GNOME Wayland, Dolphin 26.04.3 (flatpak, fedora-remote, runtime org.fedoraproject.KDE6Platform). Result: dark background like Windows 11 Explorer, white text, blue selection #0078D4.

Why Dolphin Doesn't Turn Dark (Root Causes, Verified)

1. Flatpak sandbox: inside the sandbox XDG_CONFIG_HOME=$HOME/.var/app/<appid>/config, NOT ~/.config. The host ~/.config/kdeglobals is not read by flatpak apps — they read ~/.var/app/<appid>/config/kdeglobals.
2. On GNOME the KDE platform theme is not loaded (in Plasma Qt picks it up automatically). Without it, kdeglobals is ignored entirely, and "darkness" only comes from the portal color-scheme (Qt styleHints()->colorScheme()), while the palette stays at Breeze defaults. Enable KDE themes: QT_QPA_PLATFORMTHEME=kde.
3. The runtime doesn't include adwaita-qt: org.fedoraproject.KDE6Platform only has breeze6.so style (verified: ls .../lib64/qt6/plugins/styles/). The Flathub extension org.kde.KStyle.Adwaita only works with the org.kde.Platform runtime — useless for the fedora runtime.
4. The app may overwrite its own kdeglobals with an empty file on exit (observed: 0 bytes, permissions 444). Protection: chmod 444 after writing.

Diagnostics (2 minutes)

flatpak info org.kde.dolphin | grep -E "Runtime|Environment"   # which runtime
flatpak run --command=env org.kde.dolphin | grep XDG_CONFIG_HOME # where it actually writes config
ls -la ~/.var/app/org.kde.dolphin/config/kdeglobals              # empty/missing = problem

Steps (Ready Procedure — Script Below)

1. Script: bash scripts/apply-windows11-dark.sh [app_id] (default: org.kde.dolphin). It:
   • writes the Windows 11 Dark palette to host ~/.config/kdeglobals + ~/.local/share/color-schemes/Windows11Dark.colors (for native KDE apps) AND to sandbox paths ~/.var/app/<appid>/config/kdeglobals + ~/.var/app/<appid>/data/color-schemes/;
   • chmod 444 on the sandbox kdeglobals (protection against zeroing);
   • sets flatpak overrides: QT_QPA_PLATFORMTHEME=kde, --filesystem=xdg-config/kdeglobals:ro, --filesystem=xdg-data/color-schemes:ro.
2. Segoe UI font (verify): fc-list | grep -ci segoe — if 0, install segoe-ui-linux (user already has it; in kdeglobals: font=Segoe UI,11,...).
3. Fluent-dark icons: ls ~/.local/share/icons/Fluent-dark/index.theme (user has them; [Icons] Theme=Fluent-dark already in kdeglobals).
4. Full application restart — old windows hold theme cache: close ALL windows, pkill -f dolphin if needed, reopen.

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Palette (Windows 11 dark canon): Window #1F1F1F, View #202020, Button #2D2D2D, Tooltip #2B2B2B, text #FFFFFF (inactive #C9C9C9), Selection/Focus/Decoration #0078D4, Alternate rows 6–7 units lighter than background.

Verification Without Screen Access (Agent Without Vision)

• GNOME Wayland blocks screenshots for the agent: grim → "compositor doesn't support", gdbus org.gnome.Shell.Screenshot → AccessDenied. The user sends the screenshot (in chat/Telegram).
• A model without vision can't read images — pixel analysis via PIL:

  from PIL import Image; from collections import Counter
  print(Counter(list(Image.open(path).convert('RGB').getdata())).most_common(6))

  Compare OLD and NEW screenshots: if dominants are identical — theme wasn't applied (window not restarted or config went to the wrong place).
• Screen colors are shifted by gamma/ICC (user has gnome-gamma-tool) — compare relative values before/after, not against the reference.
• OCR fallback: gpt-cli (scripts/gpt-ocr.js send) — with Cyrillic paths the attachment fails, copy the file to /tmp with an ASCII name.

Gotchas

• QT_QPA_PLATFORMTHEME=kde is mandatory: without it the entire kdeglobals is ignored (on GNOME).
• cp to the sandbox kdeglobals fails with "Permission denied" if the file is already 444 — first chmod 644.
• The sandbox kdeglobals may be created empty by the app (0 bytes) — this does NOT mean "theme reset," KConfig just created a file without keys; after writing the palette keep it at 444.
• The scheme name is resolved via ~/.var/app/<appid>/data/color-schemes/ and runtime directories — put Windows11Dark.colors there too.
• Changes to ~/.config/kdeglobals (host) also affect native KDE apps (Konsole etc.) — usually a desired side effect.
• Don't touch dolphinrc (Dolphin's personal settings live in the sandbox and don't affect the window theme).

Available Scripts

• scripts/apply-windows11-dark.sh [app_id] — idempotent installer (backup *.win11bak, palette write to host + sandbox, chmod 444, flatpak overrides). Run: bash scripts/apply-windows11-dark.sh.

References

• Flatpak theming (GTK/Qt): https://docs.flatpak.org/en/latest/desktop-integration.html
• Guide "Theme Dolphin (& QT apps) on GNOME": https://www.reddit.com/r/gnome/comments/11llvso/guide_theme_dolphin_qt_apps_on_gnome/
• Qt dark-mode detection in flatpak (root cause): https://gist.github.com/davidar/ddbe25c7038d7b88e5fddd1272724d8e