I successfully edited my List view for Orders (adding the 'client_order_ref' field) using the developer tools.
I want to do the same with the Quotations list. (i actually thought there was some inheritence between the both so that i should have only changed it in one place). But that does not give me the list ... It shows an xpath expression with an attribute name="banner_route" /sales/sale_quotation_onboarding_panel
Inheritance in Odoo: https://goo.gl/fGNfBY