DFF AR Review Installments

Summary: Uunder 'Manage Descriptive Flexfield' in AR , in the search area, I filled Flexfield code- JG_AR_PAYMENT_SCHEDULES and when I got the search results, the edit button is not getting enabled. In all other flexfields especially in AR, I am able to edit but the one under 'Review Installments' (second way to navigate to manage descriptive flexfields) when you expand the installment line arrow, it will show you the DFF but when I click on configure DFF, its not letting me edit the search result. Any idea what could be the reason?

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