Tray icon issue and `undefined symbol: gtk_module_display_init` error on NixOS

[Lab-8916100448256]

I'm having these error at picoforge startup on NixOS :

douzeb@tux12:~$ nix run github:librekeys/picoforge
Gtk-Message: 10:37:46.586: Failed to load module "appmenu-gtk-module": 'gtk_module_display_init': /run/current-system/sw/lib/gtk-3.0/modules/libwindow-decorations-gtk-module.so: undefined symbol: gtk_module_display_init
Gtk-Message: 10:37:46.751: Failed to load module "appmenu-gtk-module": 'gtk_module_display_init': /run/current-system/sw/lib/gtk-3.0/modules/libwindow-decorations-gtk-module.so: undefined symbol: gtk_module_display_init
- Touch the sensor on the authenticator

The error is not critical as the only thing that seems to not be working correctly is the tray icon that displays a default icon instead of picoforge icon.

This is happening whether I start the app with deno task tauri dev after entering nix-shell or if I start it using
nix run github:librekeys/picoforge

I tried adding libindicator-gtk3 and libappindicator-gtk3 libraries to the shell.nix file, as I have seen on internet that this could be a solution, but it did not change anything.

I found a workaround that is to run the application with env WAYLAND_DISPLAY= deno task tauri dev, but that is not ideal.

@jetcookies , do you see the same issue on your system?

[jetcookies]

My system doesn't show errors like Gtk-Message; it simply displays the default Wayland icon. While I'm unsure what causes this, the icon issue is common when running other applications, so it hasn't caught my attention.

[Lab-8916100448256]

Are you on nixos unstable @jetcookies ?
I am on 25.11, that could explain why I have these errors and you don't.

[jetcookies]

@Lab-8916100448256
I'm also on version 25.11. And flake.lock should fix inputs for all builds, so logically we should have run the same build. I don't understand what caused this.

[Lab-8916100448256]

@jetcookies
Maybe a difference in the desktop manager we use?
I'm on KDE Plasma (version 6.5.5)

[jetcookies]

[nix-shell:~]$ fastfetch --logo none
-----------
OS: NixOS 25.11 (Xantusia) x86_64
Kernel: Linux 6.12.63
Shell: bash 5.3.3
DE: KDE Plasma
WM: KWin (Wayland)
Terminal: konsole 25.8.3
Locale: en_US.UTF-8

[Lab-8916100448256]

Almost the same as on my side, just the minor version of the kernel is different.
I'm still clueless about why it does no behave in the same way on our systems.

[Lab-8916100448256]

This seems to be an issue in nixos upstream dependency. I don't see what we can do about it.
Do you agree to just document this in the troubleshooting doc and label this issue as "Won't fix"?

[jetcookies]

I agree with you. Let's proceed this way.