Add menu in dropdown list on tree view – Odoo 9
To add an additional menu in action dropdown list on tree view, we need to register “ir.actions.server” and “ir.values” on the qweb/xml file as follow. Note that code field name is using old Odoo python API. In your sale order model create the method as bellow with Odoo new API. Restart odoo and upgrade your module, you’ll have now cancel menu on your sales order tree view.