I think the controller class needs to be added to the Editable Table on the Sampler. I had a difficult time understanding where the options datasource was coming from for the LookupField. The controller class should help to make that clearer.
There is no need for a controller class for the mentioned sample since LookupField options are provided by the platform mechanisms, not the controller. In that sample, LookupField shows localized names of enum values and there is no options datasource.