As Galaxiom said, this is as you would expect it! If, for example, you were writing auto insurance for a single customer, and he had two cars...you wouldn't have a single Record, with a single Field for Make/Model, then assign that Field as the ControlSource of two different Textboxes, and expect it to contain the Make/Model of two different automobiles!
This would be a One-to-Many relationship, and normally you'd a Main Table/Main Form, with a single Record for the customer's information, and a separate, related Table/Subform, with the info on each car...whether one, two or a dozen cars.
The two Tables, and hence the two Forms (Main and Subform) would be related by a uniquely identifying, matching Field...the Primary Key on the Main Table and the Foreign Key in the related, or sub-table.
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