Setting up Update Interface so that selections made from dropdowns during the creation of the record show as the default value on the update screen.

On the creation interface for a table there are a few dropdowns, so on the update interface for the same record, I need to have the same dropdowns available in case a change needs to be made, but how do I make the default value be what was selected during the creation process? I believe it has something to do with the Selected Value input on the dropdown component configuration, On the creation interface the local variable for that list of choices goes into the Selected Value input. I tried putting a "a!defaultvalue" formula there but then when you make a change, it doesn't hold the new selection.

Also, as it may make a difference how it is set up, these dropdown's selections are drawn from related tables, not hard coded in the expression.