That panel is your systray panel, setup to be in the most obscure part of the screen. If you want to see it work, start something that uses a systray
If you want to disable it and not have a systray, it is in your autostart as
tint2 -c /usr/local/bin/.tint2oblaunchers/tint2rc &
You can disable it there
You can also
sudo medit /usr/local/bin/.tint2oblaunchers/tint2rc
and move it to where you want it OR you can autohide it, by changing the very last section from this:
# Panel Autohide
autohide = 0
to this
# Panel Autohide
autohide = 1
In Fluxbox it is in ~/.fluxbox/startup
In Xfce it is run from the Startup session