Since Caja has it's issues, I tend to prefer Dolphin. And KDE 5's Dolphin used to work very well on MATE. Then I gave the order: told comrade apt to upgrade my ancient Debian Bookworm to Debian Trixie. Of course, Dolphin is now broken — or rather it's compatibility towards MATE.

I should imagine KDE devs. won't exactly jump at the chance of making it work with it's «competing» DE, so I'm still trying to fix it with little success. This article is certainly a testament to my failure.

Yeah, I don't know how to fix that one, I guess I'll just have to accept the Windows 7 icons I used to use on Plasma.

You click any file, it opens a file dialog asking what program to use, and lists no program. You have to type the command manually. It seems to be related to broken XDG stuff, according to Reddit, letting kbuilsycoca6 daemon run seems to have solved the problem.

While this isn't technically Dolphin's fault, I'm gonna put it into it's tab because Dolphin can't do shit without launching kded6. Then, kded6 proceeds to register KNotification interface on DBus, which Telegram seems eager to bind to and will immediately send the systray icon there. And, since I'm using MATE (GTK-stuff), that crap just vanishes from the systray.

Killing kded6 makes the icon reappear, but once you do as little as opening a file on Dolphin, it will relaunch kded6.

Update: running kded5 seems to prevent kded6 from auto-launching, and also seems to make kbuildsyscoca6 irrelevant.