def _plugin_manager_changed(self, trait_name, old, new):

        if old is not None:
            old.application = None

        if new is not None:
            new.application = self

        return

    #### Methods ##############################################################
If the value for the ``dataset_id`` in the request body is already
dataset/ETHPy150Open enthought/envisage/envisage/application.py/Application._plugin_manager_changed--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/control/test/test_httpapi.py/CreateDatasetTestsMixin.test_dataset_id_collision_different_node