Operators in fields logic

I need to make a field required if another field is empty, and Iā€™m doing it with ā€œoperatorsā€, as described here, using the following code, but the field empty does not ā€œtriggerā€ the required correctly. Can you tell me how to detect if a field is empty?

$dictionary['Account']['fields']['fiscal_code_c'] = array(
    'name' => 'fiscal_code_c',
    'vname' => 'LBL_FISCAL_CODE',
    'type' => 'varchar',
    'len' => 16,
    'default' => ' ',
    'comment' => 'Codice Fiscale',
    'merge_filter' => 'enabled',
    'logic' => [
        'required' => [
            'key' => 'required',
            'modes' => ['edit', 'create'],
            'params' => [
                'fieldDependencies' => [
                    'vat_number_c'
                ],
                'activeOnFields' => [
                    'vat_number_c' => [
                        ['operator' => 'is-empty']
                    ],
                ],
            ],
        ]
    ],
);

My problem is that the operator [ā€˜operatorā€™ => ā€˜is-emptyā€™] doesnā€™t trigger the empty field. Any suggestion?

Which version of SuiteCRM are you using ?
This is-empty works from v8.4 +

I 'm working on 8.2.4 version. But if i try to enter an arbitrary value, it works instead.

                'activeOnFields' => [
                    'fiscal_code_c' => [
                          '0'
                    ],
                ],

Do you have any workarounds to suggest?

can you try with ā€œis_emptyā€ instead of ā€œis-emptyā€?

Already did. No way.

If this was all reworked and expanded for v8.4, I would advise trying it with that version. These features are new and they are not used by many, Iā€™m sure there are bugs, at least we know that for v8.4 the devs spent some extra time looking into itā€¦