In my experience this issue occurs mainly with non-local printers. Somehow the icon does not get removed from systray; a reload/restart of the panel (e.g. xfce4-panel -r) will remove it.
In my experience this issue occurs mainly with non-local printers. Somehow the icon does not get removed from systray; a reload/restart of the panel (e.g. xfce4-panel -r) will remove it.