One great thing about PonG is that it can be called from anyplace, even from other applications. But if you used custom widgetsas specified above, those widgets will not be available outside your application and PonG would use an ugly default widget instead. The way to solve this issue is with the Bonobo plugs.
To create a new control object, you use the pong_bonobo_entry_make_control function. This returns a new BonoboControl * object which you can return from a factory, this is a similar function to bonobo_control_new. The difference here is that the widget passed should implement the PongWidgetInterface as described in the previous section. This will then automatically add an implementation of GNOME::PonG::ControlInterface and you can use it in your Bonobo plugs.
This is the only difference in creating Bonobo controls for use with PonG, so for the rest of the documentation on how to create Bonobo controls, see the Bonobo manual.