Did anyone resolve this one?
I followed the advice regarding plasmarc etc and that got rid of the phantom icons but I still have two tabs on the task bar for every open program.
Easiest way - open Dolphin under Tools, Find File, search for plasma-appletsrc and delete it.
Delete the extra panels and icons, reboot or re-login and you’ll be set - worked for me with no issues.
Thanks for the help.
I had tried renaming plasma-appletsrc, deleting it etc, but no joy.
I then used the method advised in some new threads and this finally worked.