Hi ctstrist,
if the dataSource is set to a callback function it will be used only by the filtering logic which will call the callback when the value of filter input inside the drop down is changed to a new value (by default is empty). If not the dataSource function is never called. The ‘query’ argument represents the current filtering query that can be used to filter the dataSource to return a custom list of data. The ‘callback’ argument represents the function that handles the new data and populates the drop down.
Best Regards,
Smart HTML Elements Team