I needed to add some fields (15 in total) to sale.order.form's order lines. I inherited the original form and added the additional fields, but after I did it, the Product, Description and Taxes (product_id, name and tax_id) fields dissappeared.

When creating a new Quotation/SO, the mentioned fields aren't visible, but the Add a product/section/note buttons can still be used.

If I add a product, by using the arrow keys after clicking Add a product, and then save the quotation, when I edit the quotation the three missing fields appear magically.

The same happenned when I tried to add the fields with Odoo Studio, so I thought that trying to code it myself would avoid the problem.

Why does this happen? How can I make the fields visible again when creating Quotations/SO, not only when editing them?

Edit: Here´s my code:

This is the XML where I added the fields:

<odoo>
  <data>
    <record model="ir.ui.view" id="sale_order_view_inherit">
      <field name="name">sale.order.view.inherit</field>
      <field name="model">sale.order</field>
      <field name="inherit_id" ref="sale.view_order_form"/>
      <field name="arch" type="xml">
          <xpath expr="/form/sheet/notebook/page/field[@name='order_line']/tree/field[@name='price_unit']" position="after">
              <field name="list_price"/>
              <field name="vendor_discount" widget="percentage"/>
              <field name="vendor_discounted" widget="monetary"/>
              <field name="fob_total" widget="monetary"/>
              <field name="tariff" widget="percentage"/>
              <field name="tariff_cost" widget="monetary"/>
              <field name="total_tariff_cost" widget="monetary"/>
              <field name="cost" widget="monetary"/>
              <field name="admin_cost" widget="monetary"/>
              <field name="final_cost" widget="monetary"/>
              <field name="total_final_cost" widget="monetary"/>
              <field name="margin" widget="percentage"/>
              <field name="profit_margin" widget="monetary"/>
              <field name="profit" widget="monetary"/>
              <field name="sell_price" widget="monetary"/>
          </xpath>
      </field>
    </record>

class SaleOrderLine(models.Model):
    _inherit = 'sale.order.line'
    list_price = fields.Float('List Price', compute='_compute_list_price', readonly=True, store=True)
    vendor_discount = fields.Float('Vendor Discount', store=True)
    
   #  ...

   #  More field declarations of the same kind

   #  ...
    
    @api.depends('product_id')
    def _compute_list_price(self):
        for line in self:
            line.list_price = line.product_id.standard_price    

   # ...
   # More compute functions
   # ...