I see, so I could remove it, but wouldn’t I still see the same behavior, since firefox nightly apparently also uses the firefox window class?

Hmm, but I thought the StartupWMClasses in the desktop files are correct? I thought the issue is that firefox-nightly uses the firefox class in addition to the firefox-nightly class

The desktop files are named firefox.desktop and firefox-nightly.desktop, both in /usr/share/applications.

EDIT: For completeness, I also checked the window classes of the regular firefox:

It can be observed that it uses only the window class firefox, but twice?

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:

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

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.

Jop, wollte vor ca. einem Monat ein DE Ticket darüber kaufen und war auch überrascht. Und das obwohl mein Bahn Account auch schon einige Jahre alt ist und ich schon einige andere Tickets darüber gekauft habe.

(Das im DB Navigator allerdings gar nicht so leicht zu kaufen ist, da man mittlerweile seine Identität über eine Drittanbieterapp überprüfen lassen muss. Über die Apps von regionalen Verkehrsverbünden geht es noch ohne ID Check, aber so eine muss man sich dann auch erstmal raussuchen und sich dort registrieren…)

Von daher halte ich die obige Abbildung zumindest für nicht völlig realitätsfern :D

At least the sixth time even. Four cases are documented here and another one was just three months ago. This last link points to reddit, but there a manjaro maintainer also explains why it keeps happening:

Politics within the project are the issue.

The fix for these issues have been build for about a year already. But those who have access to stuff like DNS and hosting are currently incapable of making any agreement on any topic preventing trivial fixes such as this from being implemented.

They have a bugtracker: https://trac.ffmpeg.org/