Install Dropbox and get the indicator in the panel in Xubuntu 18.04 LTS

Unfortunately, upon installation of Dropbox, the indicator does not show the menu it normally does as on the Gnome desktop in Ubuntu 18.04 LTS.

To overcome this issue, open a terminal window and enter:

$ dbus-launch dropbox start -i& <enter>

Upon doing so, Dropbox starts and the indicator icon upon clicking will show the Dropbox application menu.