Eventually, every Linux user opens an app and finds a generic placeholder icon staring back from their dock/panel. It looks like the dock is broken, but it almost never is - the cause is a single line in the app’s .desktop file, and it only takes a minute to fix. Here’s how to find it and fix it yourself, on any desktop.

As the maintainer of Plank Reloaded, the most common bug report I get is “this app has the wrong icon.” It’s almost never the dock - it’s a broken StartupWMClass in the app’s .desktop file. So I wrote up how to find the right value on X11, Wayland, and KDE, and why deleting the line often fixes it.

  • angel@sopuli.xyz
    9·
    16 hours ago

    I use Firefox nightly and recently switched to Wayland (KDE). Ever since I switched, the taskbar often displays Firefox nightly with the regular Firefox icon, and the name Firefox instead of Firefox nightly. After reading your blog post I’m thinking that the culprit could be an incorrect StartupWMClass. But I don’t get why this issue never showed on X11 then.

    • zquestz@lemmy.worldOP
      7·
      15 hours ago

      Yeah something isn’t being matched right. Might want to look at both .desktop files and compare them. Probably be pretty obvious when you look. =)

      • angel@sopuli.xyz
        5·
        13 hours ago

        I just checked the .desktop file for firefox nightly. It contains only firefox-nightly as its StartupWMClass. So I went ahead and also checked the window class firefox nightly is running as and found the following: Screenshot showing the window properties of firefox nightly in the KDE system settings

        Does this mean that firefox nightly is using both, the firefox and the firefox-nightly window classes?