Empty icon is shown in GNOME Shell Favorites panel and Window list

[szszoke]

When I launch Kube Forwarder under GNOME Shell
Then the Kube Forwarder icon is not visible in the Favorites dock
And an empty space is shown instead

The same empty icon is shown when I bring up the window switcher via Alt + Tab.

The icon is showing when I search for the application in the Activities screen however:

I used the AppImage package from https://github.com/pixel-point/kube-forwarder/releases/download/v1.5.1/kube-forwarder.AppImage

When I first launched the application I was asked if I want to integrate it via the system and I clicked Yes.

I was able to reproduce the issue on my daily-driver Manjaro installation and on a fresh install of Ubuntu 20.04 inside a VM.

[4r7if3x]

In my case, I have icons visible in both the app menu and the favorites pane. But when it's not favorited, I see the default gear icon on the launch bar while running. Digging into the issue, I realized the StartupWMClass in the .desktop file has the wrong WM_Class value of Kube Forwarder while using xprop I get kube-forwarder as the correct value. Changing this fixed the issue for me...