I have a problem with GateIn 3.1 portal. I don`t know how to kill a portlet session when user is logged out from portal.
Its a bug with the product, follow the post I also faced similar issue but with JBoss EPPv5.1, wherein portlet session wasn't invalidated on logout. A major security flaw which has been fixed in EPP v5.2 and since its based on gatein am sure you would not find this issues in newer versions of gatein. Cheers!