Christian, thank you again, but I can't solve the problem. 1) @Transactional - My mistake, it was there for a previous experiment. Removed 2) Switched to Seam-managed persistence context, nothing changed 3) Now, each method has @TransactionAttribute(TransactionAttributeType.REQUIRED), nothing changed. TransactionAttributeType.REQUIRED should mean 'if a transaction exists join it' and then 'if the transaction you joined is rolled back, your changes are rolled back'. TransactionAttributeType.REQUIRED should be the default so the annotation should not have any effect. Relation between conversation and transaction is a main topic for developing real applications. I have been reading seam documentation for long time but .... Could you please answer to these questions ? a) Is the database transaction started when the conversation starts, committed when the conversation is ended (@End) and rolled back if the conversation is rolled back (@Rollback) ? This should be true, since if I call a.cancel() from the A page, the database is not changed b) When a nested conversation is started, the database transaction is nested ? If not so (a new database transaction is started) when the nested transaction is closed, the database transaction is committed and there is no way to have changes undone Thank you for your patience Fab. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4042174#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...