How far down a folder tree does Opus search for duplicates

If I search for duplicates comparing say Drive D:Folder A with Drive E:/ does Opus compare the contents of Folder A with the entire contents of Drive E?
Similarly does Synch check for copies throughout Drive E or just in the matching folder (ie Drive E/Folder A)?

Duplicates searches everywhere.

Sync only looks for files with the same paths from the two starting points..

So am I correct in thinking that if I clear drive D: of duplicates and then want to synchronise it with drive E: which still has duplicates in it, I should clear the duplicates from that drive as well before synchronising with D: otherwise I'll end up with duplicates in drive D: again?

If you do a two-way sync then it's going to copy files in both directions, yes.

If it's a one-way sync then it won't, of course.

Thanks for the clarification/confirmation.