I wrote a new column, fileds.function and tried to set the track_visibility to onchange, but it does not work.

I noticed that in the existing field "amount_untaxted" from sale.order works fine with track_visibility="always". But when I tried to override the filed and change the track_visibility='onchange', it does not work any more.

please advise.

    'amount_untaxed': fields.function(_amount_all, digits_compute=dp.get_precision('Account'), string='Untaxed Amount',
        store={
            'sale.order': (lambda self, cr, uid, ids, c={}: ids, ['order_line'], 10),
            'sale.order.line': (_get_order, ['price_unit', 'tax_id', 'discount', 'product_uom_qty'], 10),
        },
        multi='sums', help="The amount without tax.", track_visibility='always'),

Thanks very much in advance.