Version 9.0c-20160413 (Community Edition)

A sales connect to the portal to create a new quotation.
He can fill perfectly all information regarding the customer.

Order Lines Tab, he click Add an item

and then, the field product is missing. all the other field (quantity, price...) are present.
How to add back this field ?
can not make any quotation except with admin right, where the field is visible here.

thanks for your help...(again)