[Linux] Window icon is ignored on Gnome taskbar

[Balk-Z]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

When using the fyne cli to package an application for Linux the StartupWMClass specified under [LinuxAndBSD] is removed, regardless of how it is configured.

This results in the window icon in the dock being the default one. (on Ubuntu at least)

How to reproduce

1. Create a FyneApp.toml containing a StartUpWMClass entry, for example:
   [LinuxAndBSD]
   GenericName = "Test"
   StartupWMClass = "Test Window"

2. Run "fyne package -os linux -icon icon.png"

3. StartupWMClass is removed from toml and not present in resulting .desktop file

Screenshots

No response

Example code

func main() {
	a := app.NewWithID("test")
	w := a.NewWindow("Test Window")

	logText := widget.NewLabel("")
	logText.Wrapping = fyne.TextWrapBreak
	logScrollContainer := container.NewScroll(logText)

	w.SetContent(logScrollContainer)
	w.Resize(fyne.NewSize(500, 400))
	w.Hide()

	if desk, ok := a.(desktop.App); ok {
		iconResource := fyne.NewStaticResource("app-icon.png", embeddedIcon)
		desk.SetSystemTrayIcon(iconResource)

		m := fyne.NewMenu("Menu",
			fyne.NewMenuItem("Quit", func() {
				a.Quit()
			}),
		)
		desk.SetSystemTrayMenu(m)

		w.SetCloseIntercept(func() {
			w.Hide()
		})
	}

	a.Run()
}

Fyne version

fyne cli version: v1.7.0, fyne library version: v2.7.0

Go compiler version

go1.25.3

Operating system and version

Ubuntu 24.04.3 LTS

Additional Information

As far as I can tell I should be able to inject the WMClass during the package of fyne using the Linux entry section as per:
https://docs.fyne.io/started/metadata/#linux--bsd-configuration

Running Ubuntu on wayland so maybe related to #5983. Regardless, adding the StartUpWMClass to the .desktop file resolves the issues of the icon not showing only on the window and fyne should respect the [LinuxAndBSD] properties added.

[Balk-Z]

I see now that StartupWMClass is just not supported in:
https://github.com/fyne-io/fyne/blob/master/internal/metadata/data.go#L28

Is that maybe planned, or do you have another suggestion on how to make the window show the app icon after installing using the genrated make file?

[andydotxyz]

Icons should be looked up correctly - but the app must be installed for that to work.
Check that the make install worked and that the app icon is in /usr/share/applications

[Balk-Z]

The icon was present in my user .local/share/apps but it indeed was not in use/share/apps as I only did a user-install.

I will see if adding the file to your mentioned location fixes the issue once I get home, thanks!

[Balk-Z]

That didn't help. I tried both the user-install and just install.All relevant files are there:
/usr/local/share/applications/app.desktop
/usr/local/bin/app
/usr/local/share/pixmaps/icon.png
(I also moved all files to their non-/local variant)

The icons are also visible in the start menu of the OS, just not on the window itself:

fyne package -os linux -icon icon.png
and then just
make install

I must be doing something wrong...

[andydotxyz]

Aaaah - the window icon is different to the app icon.
On most OS it default to the app when no window is icon set - but not all.
Try Window.SetIcon and see if that makes a difference.

[Balk-Z]

No, that also doesn't make a difference. I tried both window.seticon and app.seticon together as well.

I must be doing something wrong, but for now I will just manually add the startupwmclass property.

I still wonder how seemingly other people don't have this issue, it's probably something gnome specific. This can be closed as it's not a bug that not all recognized-keys of the spec are implemented. Or maybe you want to keep it as a feature request perhaps.

[andydotxyz]

Try downloading another Fyne app and seeing if you see their icon.

Perhaps https://apptrix.ai/download

[Balk-Z]

I tried and it's indeed also not visible!
The same fix with the WMClass edit in the .desktop file works to fix it.

[andydotxyz]

Thanks for this.

It looks like this is somehow an issue with our metadata relating to your desktop system - can you please expand on the desktop/window manager and the taskbar configuration so we can replicate?

[Balk-Z]

Hello, sorry to getting back to you so late.

I am running Ubuntu with gdm3 -> GDM 46.2. The taskbar is pinned to the bottom of the screen and I have Dash To Panel 72 installed.

[andydotxyz]

gdm is the login manager - is it loading the default Gnome desktop?

and I have Dash To Panel 72 installed.

Do you see the same problem with the default Gnome panel?

[Balk-Z]

Hey, I assume that it's loading the default Gnome dekstop. Not sure how to check exactly, but as everything else is Gnome I assume that is too.

I tried Apptrix with Dash to Panel disabled and the default "Ubuntu Dock" enabled. Issue persists.