duplicates and replicates

I use a folder “PDF” for my pdfs. I don’t import because some of them are linked also to Sente. I indexed the folder in Devon, classified every link, then deleted the folder. after thata, I indexed again the folder and thought that all documents already in the database would apear as duplicate! some of them yes, but many old pdfs, that are already classified with a copy of the link in the database, are in black.

in my second experiment I imported the folder and then no link was red or blue. but I can understand the logic in this case. a document imported is diferent of a document indexed. even if the data is the same.

I just thought the program would automaticaly recognize duplicates… my impression is that sometimes it does! but not always.

what I’m missing?