Checkbox custom field default value

-- HikaShop version -- : 3.4
-- Joomla version -- : 3.8.7
-- Browser(s) name and version -- : Firefox

Hello,

I created a Checkbox custom field for the registration form, but I cannot set the default value to unchecked.
It does not work when I uncheck the Default value and Save it.
It would be necessary to be unchecked by default for the privacy policy checkbox because of the GDPR.

I found the solution: the value must be set to 0.