I'm dealing with a couple of unruly apps. They have a desktop file created and this "shortcut" displays correctly. But once the app launches it "disconnects" itself from the shortcut, displays with some generic icon, with missing app name and it is not grouping its windows correctly.
Here's a video showing this:
https://vimeo.com/333607681

I've also found description of the similar issue in the Latte Dock wiki:
https://github.com/psifidotos/Latte-Doc ... ution-icon

Under Gnome adding "StartupWMClass =" empty entry does the trick ( as WM_CLASS(STRING) is empty - as shown with xprop). Sadly under KDE I can't find a workaround. Any suggestions what can I try? Mayve something that could be added in taskmanagerrulesrc file (but I can't find any info about it).

As explained here, a launcher for Firefox can override the default icon in the Task Manager using the StartupWMClass desktop entry key . This works because the firefox command has the --class option for specifying the WMClass.

Does KDE/Plasma have a way to do this when launching applications like Dolphin, Krusader, etc.?