Just to let anyone else know, I’ve found a ‘workaround’. Instead of using ‘method’ as the validation method, you can use ‘required’. Which will not error if the property is null. Though obviously this is limited, for example… If I wanted to make sure the property is not null and it’s of a certain type. “currencycode is not null && currencycode.isSupportedBySeller( this.getSeller() )”