How to personalize fields in payables invoice distributions popup screen

Summary:

We would like to freeze some of the fields in payables invoice distributions popup screen for external invoices, we are able to freeze the fields based on source in the invoice header and lines, we are able to see options to edit all the fields except the distributions popup. we tried to view in Source mode but still not able to see any child components for distributions button. When tried to open distribution popup page , we are not able to click on any option when the distribution page is open, neither select content nor structure.

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