you have 2 recordsets on the page
1) the main recordset that is used to populate the other form elements on the page
2) The one for the dynamic list.
the value stored in the main recordset for the column that is driven by the list will be used to set the selected item in the list.
The main recordset is already filtered by the passed in ID, Use the main recordset to set the selected item in the list.
to do this, Click the lightning bolt next to set selected and select the corresponding column from the main recordset.
should have read: