Task Manager Not Grouping by .desktop file (Zen Browser)

I am using Zen browser and I would like to get separate icons on the task manager for regular and private windows. With that in mind I created a .desktop file for the private zen browser with a separate name, icon, and StartupWMClass. I then created a rule in the Window Rules that any window with “Private Browsing” substring would have the property of this .desktop file forced. I can see that it does apply that file when I click detect window properties in the rule. However the grouping does not seem to be working. The same grouping for Firefox does seem to be working (note that to check this I remove check whether it’s zen browser or not, and I am still using the .desktop file for zen), however the only difference (based on detect window properties) between a regular firefox window and private firefox window is that the desktop file is different, the same holds true for regular zen window and private zen window, but results in a different behavior for the task manager. I’m a new KDE user, but I am at a loss on how to explain this difference. Screenshots for everything I mentioned below. Any help on how to resolve this and get separate groupings for zen on task manager based on private/regular window would be appreciated.




Zen Regular Window Properties

Zen Private Window Properties

Firefox regular window properties

Firefox private window properties

The taskbar, there’s only one window grouped under the custom .desktop file (the firefox private window), and the there’s multiple windows under zen which includes the private windows
image

Hi - just checking, if you’re forcing a Desktop file name, does it make a difference if you omit the .desktop at the end?

For what it’s worth, I don’t use the exact same window rules - but I do have a few that force a Desktop file name, and just using the part before the .desktop seems to work on my device.

It doesn’t seem to make a difference one way or the other, for firefox it works with or without the .desktop at the end and for zen it doesn’t regardless. I believe having either is acceptable

Ah, got it - just in case there’s a helpful clue in the info, could you please share your basic system information from the Info Center app? The Copy Details button is the easiest way to get that ready to paste in:

Operating System: Fedora Linux 42
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.0
Kernel Version: 6.14.9-300.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 20 × 13th Gen Intel® Core™ i5-13600K
Memory: 31.1 GiB of RAM
Graphics Processor 1: AMD Radeon RX 6800 XT
Graphics Processor 2: Intel® Graphics
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: Z690 UD DDR4