Please check the access rules in your domain model for the name attribute in the entities Location and Teacher, they should be Read,Write. Also check if there is Read,Write access on the associations that you use to get to these entities.
The last thing that can cause this is that the editability of these fields are set to ‘Never’, you can check this in the properties in your modeler.
With kinds regards,
Bryan de Wit
You have used text box input widget but you should use the reference selector widget. That will result in a dropdown selection like you also have for the course