You can remove the field optional
attribute.
Example:
<record id="view_order_form" model="ir.ui.view">
<field name="name">sale.order.form</field>
<field name="model">sale.order</field>
<field name="inherit_id" ref="sale.view_order_form"/>
<field name="arch" type="xml">
<xpath expr="//field[@name='order_line']/tree/field[@name='qty_invoiced']" position="attributes">
<attribute name="optional"></attribute>
</xpath>
</field>
</record>
To do it through the UI, Go to Technical / User Interface / Views
and look for sale.order.form
then add a line under Inherited Views
Set a view name (sale.order.form.inherit
)
and set the Architecture
to:
<xpath expr="//field[@name='order_line']/tree/field[@name='qty_invoiced']" position="attributes">
<attribute name="optional"/>
</xpath>