You should be able to activate the Rowkey by going to the Entity window. If the Rowkey is not activated, there should be command button to activate it.
What is “ENTITY WINDOW” per say ? is it entity details ? because I cannot see any edit option there as well .
Can you send me a screenshot of the window that we can use to enable the row key . Because as you can see from the image I have provided it is not possible to do it using entity configuration.