It gives me an idea : would it be interesting for a librarian to have a "search page" with 'simple' AND complete/MARC search ?

YES! Absolutely! The complete MARC search is powerful, but too cumbersome for day-to-day circulation-related searching. Librarians need a search akin to the OPAC's 'Advanced Search' easily at hand in the Intranet interface.

If this sounds good, enter a "bug" at bugs.koha.org as reminder.

I'll do that. -- Owen