I tried a custom field with:
return (new CSimpleField('table','data','name'))->GetHtml();
or
return CustomFieldFactory::GenerateField(json_decode('{"FieldType":"normal","FormattingOptions":{"Type":"currency","ThousandSeparator":".","DecimalSeparator":",","NumberOfDecimals":2,"CurrencySymbol":"€","CurrencyPosition":"right_space"},"OrderFields":[{"path":"total","key":"total","value":"500.00","dataType":"","source":"data","fieldType":"normal"}],"Text":""}'))->GetHtml();
The following message appears during saving both custom fields: Data could not be inserted
The chrome console is showing the following error message as well:
customFields_bundle.js?ver=5.3.2:28 Uncaught Error: [mobx] An invariant failed, however the error is obfuscated because this is an production build.
at p (customFields_bundle.js?ver=5.3.2:28)
at f (customFields_bundle.js?ver=5.3.2:28)
at customFields_bundle.js?ver=5.3.2:28