Project list : can't see all fields

Hello,

i use a lot of customized fields in project (lot of contact type, etc...), some are linked to list, some are only varchar (max 200).
When i want to make specific view in project list, i can't see all the field.

ie : i have a field "prestataire" (VARCHAR 100) that i can't see in field list to add to the project list...

Any idea ? Too many custom fields ?

Regards,