For example,
the rich:listShuttle has a target/sourceRequired-Property and does not have a requiredMessage-Property, the same is for validator (has no validatorMessage).
Look at h:inputText, it has properties like required, requiredMessage, validator, validatorMessage.
Hello,
You are right, it's a bug: https://jira.jboss.org/jira/browse/RF-6794