I see seam-gen was updated today to prepare for general targeting of Jboss 4.2. I gave it a try, and bumped into issue http://jira.jboss.com/jira/browse/AJSF-32 , which I also saw on my own when I tried targeting 4.2 a few weeks ago. It's easy to reproduce, and I added comments to the Jira issue describing what I'm seeing.
In a nutshell, users running a freshly generated seam-gen project who have added a new-action, quickly see:
when clicking on the generated page's button.
Just wanted to let you know since this seems like it will impact anyone using seam-gen from CVS at this point.