I want to link a form and a subform based on a common ID field. I have linked the Master/Child fields and added an event procedure such that when I select a new entry on the master form, the subform updates automatically with the corresponding entries. This works perfectly when the ID field size in both tables is set to Long Integer, but when i try to set the ID field size to Replication ID, the subform is shows up blank. I've tried this for existing tables and also creating tables from scratch. Is there any reason that the Replication ID size should keep a subform from updating properly?