The nickel_no_fmon.sh worked perfectly, thank you very much !
But I suppose that it can happens again because sometimes the shelves who appear are the ones built by calibre, sometimes the ones built by "auto shelf"...
I tried to log out to start with a fresh database free of shelves, but it already contains some ones...
I don't understant how it works.... I'm lost !
Do you know a way to clean up the part of the database talking about shelves ??