This short program shows how to write an applet for the GNOME2
panel. 

Applets are Bonobo components (the component system used in
GNOME). However, pretty much all of this component stuff is wrapped by
the panel-applet library. So, when programming the applet we deal with
a regular GTK+ widget (a subclass of GtkEventBox). This PanelApplet
widget has a few new signals so that the applet can be notified of
changes in its environment (mainly size and orientation of the
panel). The GConf-related functions are not wrapped for a lack of
GConf/ocaml bindings.

The .server file contains information for the activation server so that
it can launch the applet executable. Make sure that :

  - the .server file is installed in a place the activation server can
  find : 
      - $prefix/lib/bonobo/servers 
      - some directory mentioned in 
          $prefix/etc/bonobo-activation/bonobo-activation-config.xml
      - some directory in the BONOBO_ACTIVATION_PATH env variable.

  - the executable is at the place mentioned in the .server file

  - the activation server can fork a working caml program (so you
    may have difficulties with CAML_LD_LIBRARY_PATH ; it's probably
    easier to use an executable compiled with ocamlopt).

If your applet use an external XML file for the UI, it must be
installed in the right place ($prefix/share/gnome-2.0/ui should work).

To test the applet, launch the executable in a terminal window, then
right after that, add the applet to the panel using the panel
menu. The panel should be using the executable you launched and you
should see whatever messages your applet send to stdout/stderr.
The gnome-panel package has a panel-test-applets executable that you
can find useful for testing how your applet reacts to the signals sent
by the panel (size, orientation, etc.).