I forgot to mention:
My old app with richfaces 3.1.0RC5 does not have this problem. This app runs on tomcat5.5 with myfaces as jsf implemantation
My new, migrated app with richfaces 3.1.4GA runs on tomcat 6 (and jsfRI) shows this issue.
it seems to be a problem with the jsf RI implementation. I get the same problem with mojarra-1.2_08-b06-FCS
But with myfaces-core-1.2.2 it renders correctly.
But i am bound to RI. What shall i do?