How can I set what should be displayed in the form header?

I have a Pricelist table (Fields: Unit of measure, Price per unit) linked to Vendor and Item tables. The form header shows Unit of measure, which I don’t want, see attachment. How can I set what should be displayed in the form header?

Hello,
It is the first text column automatically.
You are able to change that in table Fields definition → Advanced settings → Show in the record description

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Regards
Michal