Attempt to launch causes error message: GDBus.Error:org.freedesktop.Dbus.Error.ServiceUnknown: The name org.xfce.Panel was not provided by any .service files I’ve tried some of the solutions offered in the task bar problem without success.

Also, when I tried to track down the problem on Synaptic, it reports Depends: xfce4-panel (<4.13) but 4.14.3-1~18.04 is to be installed. That’s also something that is beyond my experience to fix. Thanks for all your efforts!