In order to enable the "indicate which records caused the scenario to fire" checkbox, you must select a date and time column for the aggregations. This functionality is leveraging a feature in the underlying CAS action which requires a date/timestamp column. See the screenshot below for the location of the date column selection box on the scenario properties screen:
SAS' 10th Year as a Category Leader
Chartis names SAS a leader in both Model Risk Governance and Model Validation