def on_backend_added(self, sender, backend_id):
        """
        Signal callback executed when a new backend is loaded

        @param sender: not used, only here to let this function be used as a
                       callback
        @param backend_id: the id of the backend to add
        """
        # Add
        backend = self.req.get_backend(backend_id)
        if not backend:
            return
        self.add_backend(backend)
        self.refresh()
        # Select
        self.select_backend(backend_id)
        # Update it's enabled state
        self.on_backend_state_changed(None, backend.get_id())