Double Star Measurements

Suppose you want to do double star measurements by using "Measure PA / Sep" from the Tools menu ...

Prior to selecting "Measure PA / Sep", if one labels the primary as "Star 1" and the companion as "Star 2", will VPhot automatically centre the concentric circles on the centroid of each star?

If not, how does one do this - getting the circles accurately on top of the centroid would seem to be essential to get good measurements?

Cheers
Paul YPFA