My precedent problem have been resolved by the maling list. Now I got "value not in database" helpers message when I select more then one entry of the dropbox... The problem is coming from the web2py recent update 1.80.1, 1.81.4. The same app with 1.79.2 no problem (I package app from 1.80.1 and install it in 1.79.2). Here my function code : db.atable.field2.widget=multiselect_widget db.atable.field2.requires=\ IS_IN_DB(db,'auth_user.id','%(first_name)s %(last_name)s (%(id)s)',multiple=True) form = crud.create(db.atable) Jonhy