Dear devs,
a small proposal: would it be fine to expose transaction timeout defaults as a property in the transactions subsystem ?
AFAIK you have to include it in the coordinator-environment element. ....

       <subsystem xmlns="urn:jboss:domain:transactions:1.0">
            <core-environment socket-binding="txn-socket-process-id"/>
            <recovery-environment socket-binding="txn-recovery-environment" status-socket-binding="txn-status-manager"/>

            <coordinator-environment enable-statistics="false" default-timeout="300" />

        </subsystem>

kind regards,
Francesco Marchioni