Chrome doesn't detect light/dark theme change on Linux (KDE/Flatpak) about com.google.chrome

[evan-a-a]

Interesting, the dark mode detection implementation in Chromium uses the portal system, so this should work. Relevant code:

https://github.com/chromium/chromium/blob/main/chrome/browser/ui/views/dark_mode_manager_linux.cc

Do you have any dbus binding errors in the logs at startup?

[dmig]

Yes, there is one, related to kwallet (not installed):

$ flatpak run com.google.Chrome 
Gtk-Message: 18:11:58.704: Failed to load module "canberra-gtk-module"
[0220/181158.786010:WARNING:chrome_main_linux.cc(80)] Read channel stable from /app/extra/CHROME_VERSION_EXTRA
[0220/181158.967293:WARNING:chrome_main_linux.cc(80)] Read channel stable from /app/extra/CHROME_VERSION_EXTRA
Gtk-Message: 18:11:59.018: Failed to load module "canberra-gtk-module"
Gtk-Message: 18:11:59.065: Failed to load module "colorreload-gtk-module"
Gtk-Message: 18:11:59.066: Failed to load module "window-decorations-gtk-module"
[2:2:0220/181159.100915:ERROR:atom_cache.cc(224)] Add _ICC_PROFILE_1 to kAtomsToCache
[2:2:0220/181159.114903:ERROR:object_proxy.cc(576)] Failed to call method: org.kde.KWallet.isEnabled: object_path= /modules/kwalletd5: org.freedesktop.DBus.Error.ServiceUnknown: org.freedesktop.DBus.Error.ServiceUnknown
[2:2:0220/181159.114962:ERROR:kwallet_dbus.cc(112)] Error contacting kwalletd5 (isEnabled)
[2:2:0220/181159.117763:ERROR:object_proxy.cc(576)] Failed to call method: org.kde.KLauncher.start_service_by_desktop_name: object_path= /KLauncher: org.freedesktop.DBus.Error.ServiceUnknown: org.freedesktop.DBus.Error.ServiceUnknown
[2:2:0220/181159.117801:ERROR:kwallet_dbus.cc(81)] Error contacting klauncher to start kwalletd5
[2:2:0220/181159.118298:ERROR:object_proxy.cc(576)] Failed to call method: org.kde.KWallet.close: object_path= /modules/kwalletd5: org.freedesktop.DBus.Error.ServiceUnknown: org.freedesktop.DBus.Error.ServiceUnknown
[2:2:0220/181159.118319:ERROR:kwallet_dbus.cc(503)] Error contacting kwalletd5 (close)
INFO: Created TensorFlow Lite XNNPACK delegate for CPU.
Fontconfig error: Cannot load default config file: No such file: (null)
Fontconfig error: Cannot load default config file: No such file: (null)

but nothing else

[evan-a-a]

I can't reproduce this on GNOME 46 Beta (Fedora 40 branched). Can you confirm the DE and version you are using?

[dmig]

It is:

Operating System: SteamOS 3.5.15
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.107.0
Qt Version: 5.15.9

running Xorg

[evan-a-a]

Unless you've set up your environment differently, KDE doesn't use dconf for configuration and thus won't reflect those changes to Gnome settings that the dconf commands modify. You'll need to change things the KDE-way, which most easily is done through the settings utility.

[dmig]

KDE way is unrelated here.
I actually use 2 commands to change theme:

plasma-apply-colorscheme BreezeDark
gsettings set org.gnome.desktop.interface color-scheme prefer-dark

[evan-a-a]

I've verified that this works as intended on KDE 6 RC2 (Fedora 40), so this is either a KDE 5.27 bug or an environment issue.

Can you verify that xdg-desktop-portal and xdg-desktop-portal-kde are running in your environment? Both are necessary to emit the signal that notifies Chrome of the theme change.

ps aux | grep xdg-desktop-portal

or the systemd way

systemctl --user status xdg-desktop-portal.service
systemctl --user status xdg-desktop-portal-kde.service

[dmig]

I verified that both processes are running:

deck        3489  0.0  0.6 1225912 95072 ?       Ssl  Feb16   0:26 /usr/lib/xdg-desktop-portal-kde
deck      287148  0.0  0.1 593832 19764 ?        Ssl  00:12   0:00 /usr/lib/xdg-desktop-portal

Likely it's the environment issue, but I don't trust flatpak because had to fix several old known bugs manually.

There is another thing that differs from native package: under 'Appearance' menu there is a dark mode selector (light/dark/system), which is missing in flatpak Chrome. I wonder if it's shown depending on the environment or enabled using flags?

[evan-a-a]

I don't have those options either and dark mode still follows the system, as expected.

Would you mind waiting for KDE 6 to release (it's due next week) and seeing if the issue persists?

[dmig]

I don't think KDE 6 is coming to steam deck any soon. Will continue investigating.