Install xfce4-statusnotifier-plugin by entering the following commands in the terminal:
sudo apt update sudo apt install xfce4-statusnotifier-plugin
Description:
plugin to display status notifiers in the Xfce4 panel
A small plugin to display status notifiers, including application indicators, in the Xfce4 panel as described in freedesktop.org StatusNotifierItem specification. Status notifiers are a modern alternative to the system tray.
Homepage: https://goodies.xfce.org/projects/panel-plugins/xfce4-statusnotifier-plugin
Version: 0.2.1-0ubuntu1
Section: universe/xfce