Thank you for your post. I am not sure about the bug you said but normally you can create a foreign key by drawing the relationship between two entities directly in the diagram editor. Did you try that?
Version 7.2 is pretty out of date (released about 10 years ago). There are many fixes and enhancements in this 10 years. The problem you encountered should be fixed already.
I tried but for whatever reason, VP doesn’t want to understand ^^
Is there a programmatical / manual way to “force” to create foreign key if the first way doesn’t work.