Currently I am identifying faces in pictures, the faces are being added to the metadata in the pictures. Until now the rectangles with the faces I tagged were visible in the picture (from within GC). But since some days the rectangles are not shown anymore. The metadata are there however. And if I try to tag a new face at (approx) the same spot with the same name I get this messge 'Already exists, only one region will be added ' (or something like that).
I noticed the setting 'Display XMP Faces/regions' and I have turned it off and on again, nothing happens

Maybe I am not aware of how the faces database works, should I rebuild the database?
One thing more: if I tell GC to identify faces in a picture (with the metadata already there, but without the rectangles) it says that some faces have been recognised and then some of the rectangles are shown, but not all
Anyone knows what I should do?
And...is there a good manual about the face recognition and how to use the faces database. The GC manual is good, but I feel there is some general information about the way the database works, missing
Thanks for any advice
Snellius