In Kubuntu 22.10 there is this option of a popup list of clipboard actions when sending a file/folder or link to the clipboard, involving the applications associated with that type of file or link.
In the file manager, Dolphin, when copying a file (which sends it to clipboard), the list coincides with the "Open with" context menu:
If a URL is copied in a browser other than Firefox (tested Falkon, Opera, Vivaldi) the same happens with copied ("clipboarded") links (I've heard that in Chrome/Chromium it works too).
New actions can be added beside the listed applications, in ":
Plasma integration addon is installed in Firefox. As far as I know, only Falkon has an UI based on Qt, the rest, including Chrome and Chrome-based, are GTK like Firefox. So this should work in Firefox.
Why doesn't it? How to make it work?
I don't just wait for an answer, but I'm looking for it, so I risk finding one and having to post it under my own question! Again. Here it is:
As far as I see it, it's the other way around from how I've presented the situation: the clipboard settings have an exclusion list for the actions per window, and most browsers were listed there under Configure clipboard (right-click the tray widget) -Action menu - Exclude windows:
So, I imagine the "problem" Firefox had should have appeared in most browsers, only they ignored that list for some reason, but not Firefox - or maybe their WM_CLASS name was not entered as required, but Firefox's was.
The answer here was to remove from that list
firefox
andNavigator
.