For the time off app we should be able to dynamically filter the company in the time off type list. I have worked with an Onchange function which also works perfectly. The problem is only when I open the form that domain should not apply yet. There is no list of items to see as long as I set employee field for example. This is not a problem for the managers, but it is for the employee who wants to request leave. He now does not see a list, which must also be filtered by company. Here's my code:

@api.onchange('employee_id')
def _onchange_employee_id(self):
    for rec in self:
        return {'domain': {'holiday_status_id': [('valid', '=', True),
                                                 ('company_id', '=', rec.employee_id.company_id.id)]}}
@api.onchange('mode_company_id')
def _onchange_mode_company_id(self):
    for rec in self:
     return {'domain': {'holiday_status_id': [('valid', '=', True),
                                                 ('company_id', '=', rec.mode_company_id.id)]}}

@api.onchange('department_id')
def _onchange_department_id(self):
    for rec in self:
        return {'domain': {'holiday_status_id': [('valid', '=', True),
                                                 ('company_id', '=', rec.department_id.company_id.id)]}}