Create the user interface

           create_ui is a method called during the Delegate's
           initialisation process, to create, add to, or modify any UI
           created by GtkBuilder files.

def create_ui(self):
        """Create the user interface

           create_ui is a method called during the Delegate's
           initialisation process, to create, add to, or modify any UI
           created by GtkBuilder files.
        """
        self.entry = gtk.Entry()
        self.widget.add(self.entry)