Comment 96 for bug 684982

(In reply to Reinhard Kahle from comment #91)
> This is, indeed, a great improvement - I was waiting the same 13 years for a solution as Hans-Peter!

Glad to hear that!

> But as you kindly rise hope for more fun things, here still one feature I'm missing: essentially the same "bug" still occurs when I use KDE/plasma's "activities": Firefox restores (now) the windows on the correct desktops - thanks again! - but the desktops are mixed up on different activities (a window of desktop 1 in activity 2 may be restored on desktop 1 but on activity 1) . Of course, there might be some specific interferences with the activity handling of plasma (which, I think, is not used by many people and even less supported); but the similarity of the problem is striking, and as you was able to solve the desktop problem, I'm wondering whether it could be equally easy to solve the activity problem. (I'm not sure whether this should be reported as a new bug??)
>
> Currently I use: kubuntu 19.10; kernel 5.3.0-46; KDE-Plasma version 5.16.5. But the problem is as old as the activities of plasma.

Well, I haven't heard about KDE Activities up 'till today, so I'll need to investigate this a little more before I can say anything relevant. Certainly, it deserves its own bug - which would be most appropriate for you to file - referencing this one.
I have to say, though, that the part of the appeal of fixing this bug was that it was beneficial for Linux users across various WMs, Mac OSX and - since late version 10 - Windows users.