Pass data to many2one widget - odoo

Question

I have a custom module with the following simple data structure:
class Site(models.Model):
_name = 'sites.site'
site_name = fields.Char(string="Site Name")
contact_in_site_role_ids = fields.One2many(comodel_name="sites.contact_in_site_role", inverse_name="site_id", string="Site Contacts", required=False, )
class SiteRole(models.Model):
_name = "sites.site_role"
role_name = fields.Char(string="Role Name")
class ContactInSiteRole(models.Model):
_name = "sites.contact_in_site_role"
site_id = fields.Many2one("sites.site",string="Site")
contact_id = fields.Many2one("res.partner",string="Contact")
role_id = fields.Many2one("sites.site_role",string="Site Role")
role_detail = fields.Char(string="Role details")
This is currently managed by the following form:
<record model="ir.ui.view" id="site_form_view">
<field name="name">site.form</field>
<field name="model">sites.site</field>
<field name="arch" type="xml">
<form string="Site Form">
<sheet>
<group>
<field name="site_name"/>
</group>
<notebook>
<page string="Site Contacts">
<field name="contact_in_site_role_ids" widget="one2many_list">
<tree>
<field name="contact_id"/>
<field name="role_id"/>
<field name="role_detail"/>
</tree>
</field>
</page>
</notebook>
</sheet>
</form>
</field>
</record>
This works well, apart from when clicking to add a contact on the Many2One widget on the "Edit Site Form", it prompts again for the site. How do I remove the "Site" option from this popup form, and have the relevant site passed from the parent form:

Answer 1

Try to pass like below and see
<field name="contact_in_site_role_ids" widget="one2many_list" context="{'default_site_id':parent.id}"/>
The concept here is we can initialize the child element values by passing them in the context like:
{default_child_field: value}