Hi all,
since a few weeks I have a problem with the deja-dup backup software: previously, when the backup was triggered, the deja-dup icon would appear in the tray, allowing to monitor the state of the backup process. Now the icon does not appear anymore, though the backup process is correctly working as before.
All the other programs that usually showed their icon in the tray still work as expected: only deja-dup has disappeared.
The same happened to me with NetworkManager. I quit graphical session, logged into terminal and moved .config/plasma-org.kde.plasma.desktop-appletsrc. Upon graphical login the applet of NetworkManager worked again.