"Yes, it is, but it often has no data"
How can it have no data? Even when creating a new record the link field in the subform will immediately have the same value as its master link field in the main form?
But if you have multiple copies of the same subform on a main form, I don't see any way that you can tell which one you are in, unless you set up some data to tell you. I would have thought that the link child value woud be sufficient, otherwise how does the subform know which records to display?
But if you insist that is not so, then the only other approach that i can see working is to use the Enter event procedure of every subform container control and set a public variable to a distinct value which you can then refer to in your subform code.
