While using Fullscreen Preview to switch desktops, i.e.:
Desk_1 -> Fullscreen_Preview -> Desk_2
and than backwards, etc., the inner order of the grouped items in the taskbar get messed up.
Group like this:
(crome_window_1, crome_window_2, crome_window_3, crome_window_4)
after a few switches becomes like this:
(crome_window_4, crome_window_3, crome_window_2, crome_window_1)
If the desktop switching is performed by a direct shortcut assigned to this specific desktop, the groups inner order preserved correctly
Same is with the "Taskbar Pager", it preserves the order correctly.
Only switching via the "Full Screen Preview" creates this abnormality. (And I suspect, Window Catalog cause this too, since both are part of the same "Desk Control" plugin). For easier reproduction, perform several switches.
Full Screen Preview is a very convenient feature, it gives you a brief overview, to which desktop you want to switch by glancing at its content. And by mapping it on an extra mouse button, it makes it the most "friction-less" way to manage several desktops, and working across several projects productively.
The issue described, while not "critical", is a very annoying one, since it slows down the workflow, and doing the opposite of organizing the working environment (which is the reason we use virtual desktop sw in the first place...).
So I hope this issue may be fixed soon