testBean should be session scoped in order this to work.
And b.t.w. if you using ajaxSingle at support you could remove region and immediate=true .
thanks for your reply, Ilya!
I tried your advice and it does work, but I can't see why it'd work for session not request. My bean really has to be request scoped. Is there a way to make this work in request scope?
I found another similar discussion that's why I wrapped my selectOneMenu with <a4j:region> tags, but it doesn't work.
Am I on the wrong track? I just want to show some additional input fields based on user's selectOneMenu selection. This should be a very common use-case? Can it be accomplished some other way?
your bean have to be stored between requests. There are different ways - session scope, long running conversation if seam used, or a4j:keeAlive. Read about the problem there http://livedemo.exadel.com/richfaces-demo/richfaces/keepAlive.jsf;jsessionid=6B48599000B855C89CEA7EF0D08E41E3?c=keepAlive&tab=usage and the same write-up in wiki faq.