First, install libappindicator1 once by:
sudo apt-get install libappindicator1 <enter>
Now, each time, the below commands need to be executed to get the dropbox icon in the panel.
dropbox stop -i <enter>
This command will stop the dropbox daemon.
dropbox stop &&DBUS_SESSION_BUS_ADDRESS="" dropbox start <enter>
This command starts dropbox and displays the icon in the panel.
Icon came back. This workaround was at http://askubuntu.com/questions/732967/dropbox-icon-is-not-working-xubuntu-14-04-lts-64
Now, the key command is dropbox stop &&DBUS_SESSION_BUS_ADDRESS=”” dropbox start and you need to enter this each time. Clicking on the dropbox icon in the menus does not work.