I have a test company created with 2 contacts.

I would like that in my module when I select the Company (marked is company) that in another field it only shows contact for that company

In developer mode, I found contacts to have name "child_ids" and I thought maybe if I added this:

<field name="res_partner_id" domain="[('child_ids', '=', True)]" />

it would work:

However it gives error:

ProgrammingError: operator does not exist: integer = boolean

LINE 1: SELECT "parent_id" FROM "res_partner" WHERE "id" IN (true)

^

HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.

Any ideas on how to fix this?