Section 1.3 of the E2E Simple Datatypes Editor Test script specifies attempts at changing a Read-Only XSD file. All actions and links should be disabled, but I found the "Create subtype of this datatype..." link was enabled. I clicked it and entered a name for the subtype. When I clicked OK button, I got an error indicating the XSD file coud not be modified.

The Create link should be disabled when the model is Read-Only.