[AccessD] New vs. Obsolete Products list

A client wants to consolidate her list of products, reducing a rather
ungainly list of slightly different variants to a much smaller selection.
This occurs in the Transactions table, and the ProductID is presented there
as a combobox. I added a field to the Products table, called Obsolete.
There is no intention to backfill/correct the existing rows in
Transactions, but rather to restrict new Transactions to the Products that
are not obsolete. I have created two queries to present these two lists.
While the user is browsing existing records, I want the complete list, but
when inserting a new row, I want to change the RowSource to the query that
hides all the Obsolete products and presents only the revised list.

My question is this: on what event should I swap the RowSource? I'm not
quite sure how to approach this. Once I decide on which event to use, the
rest is simple, but which event is the right one? The code should kick in
and swap the RowSource only on entering a new record.

TIA,
Arthur

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