When you go to "Use Rule" on the "Find and Merge Duplicate Contacts" page, you get a new page that has 2 fields, one called "Select Group" and the other called "No of contacts to find matches for" with a default value of 3. What is this second field and how does it work? The documentation I've found so far doesn't include it.
I'm on wordpress 4.7.3 and civicrm 4.7.18.
Thanks, Ruth