📖Double Icons in Plank

One app, two same icons

When launching a Flatpak app, you see two icons of this app in the Dock.

Example of the Double Transmission Icon

This is a known issue related to the Flatpak and Plank interaction. If it still persists in your system, there is a solution.

What you need is to edit the .desktop file of the target app by adding the StartupWMClass=<VALUE> string.

Let's take the Transmission app as an example in the following guide.

1. Find out the <VALUE> you need to add to StartupWMClass=

   • Launch the app which shows the icon duplicate.

   • Open the Terminal and run: xprop WM_CLASS. Your mouse cursor must turn into a cross.

   • Hover the cursor over your app window, and click. In the Terminal, you will see the <VALUE> you need to add.

Value found in the Terminal

2. Find and then open in the text editor the .desktop file of the app. You can search for the desktop file of your app in the same direction where the Transmission desktop file in the example is.

/home/<USER_NAME>/.local/share/flatpak/app/com.transmissionbt.Transmission/current/3d0fb3864db64add64e036679cccf94bd31d38ddcdd5b22ea263ad742b9ff458/export/share/applications/com.transmissionbt.Transmission.desktop

3. In the end of the [Desktop Entry] section, insert StartupWMClass=transmission-gtk string where you will have your app value instead of transmission-gtk.

Added StartupWMClass to the .desktop file (example)

4. Save changes and reboot.

5. Launch the app. There must be no more icon duplicates in the Dock.

After the app version is updated, an icon duplicate may re-appear in the Dock.

In this case, you need to repeat the procedure above and add StartupWMClass=<VALUE> to the app .desktop file again.