docs: def register_view(self, view):
          """Called when the View was registered
          """
          super(StateTransitionsListController, self).register_view(view)
  
          def cell_text(column, cell_renderer, model, iter, data):
              t_id = model.get_value(iter, self.ID_STORAGE_ID)
              in_external = 'external' if model.get_value(iter, self.IS_EXTERNAL_STORAGE_ID) else 'internal'
              # print(t_id, in_external, self.combo[in_external])
              if column.get_title() == 'Source State':
                  cell_renderer.set_property("model", self.combo[in_external][t_id]['from_state'])
                  cell_renderer.set_property("text-column", 0)
                  cell_renderer.set_property("has-entry", False)
              elif column.get_title() == 'Source Outcome':
                  cell_renderer.set_property("model", self.combo[in_external][t_id]['from_outcome'])
                  cell_renderer.set_property("text-column", 0)
                  cell_renderer.set_property("has-entry", False)
              elif column.get_title() == 'Target State':
                  cell_renderer.set_property("model", self.combo[in_external][t_id]['to_state'])
                  cell_renderer.set_property("text-column", 0)
                  cell_renderer.set_property("has-entry", False)
              elif column.get_title() == 'Target Outcome':
                  cell_renderer.set_property("model", self.combo[in_external][t_id]['to_outcome'])
                  cell_renderer.set_property("text-column", 0)
                  cell_renderer.set_property("has-entry", False)
              else:
                  logger.warning("Column has no cell_data_func %s %s" % (column.get_name(), column.get_title()))
  
          view['from_state_col'].set_cell_data_func(view['from_state_combo'], cell_text)
          view['to_state_col'].set_cell_data_func(view['to_state_combo'], cell_text)
          view['from_outcome_col'].set_cell_data_func(view['from_outcome_combo'], cell_text)
          view['to_outcome_col'].set_cell_data_func(view['to_outcome_combo'], cell_text)
  
          if self.model.state.get_next_upper_library_root_state():
              view['from_state_combo'].set_property("editable", False)
              view['from_outcome_combo'].set_property("editable", False)
              view['to_state_combo'].set_property("editable", False)
              view['to_outcome_combo'].set_property("editable", False)
          else:
              self.connect_signal(view['from_state_combo'], "edited", self.on_combo_changed_from_state)
              self.connect_signal(view['from_outcome_combo'], "edited", self.on_combo_changed_from_outcome)
              self.connect_signal(view['to_state_combo'], "edited", self.on_combo_changed_to_state)
              self.connect_signal(view['to_outcome_combo'], "edited", self.on_combo_changed_to_outcome)
  
          view.tree_view.connect("grab-focus", self.on_focus)
          self.update(initiator='"register view"')