Once duplicate file searching and comparisons are complete, the result report will provide a group-based display of the results.
Duplicate file groups are separated by lines and are displayed with alternating background colors. You can hover your mouse over any file within a duplicate group to get information about the overall size of that group (along with other information).
Groups also have a unique number (a group index) associated with them, visible (by default) as a column within the result report.
Which Duplicate File Group Entry is the Original?
When viewing and managing duplicate file groups, don't be confused by the concept of duplicate file originality. Duplicate File Detective has no way of knowing which duplicate file in any given group is the "original", and it doesn't attempt to make such determinations - it simply shows all files discovered during the duplicate search process. Decisions regarding which files to keep (or otherwise process) are left entirely up to the user.