Hi @MaxonL16591286,

What is meant by source property ?

--> While exposing the property, it will show the list of classes if the same property is available in different classes.

--> If you are doing the respective class, it will be in the very first row, and other classes will show in the remaining rows. 

Note: If you want you can check the box, by defaulty it is unchecked.

--> You can also check by opening the advance tab of the property and then --> Optimized for classes

Thanks,

Ashok