Many times, when searching for Tapestry-relates stuff with Google, the mailing lists, which are a very valuable source of information, are not shown due to the limited number of links. However, you can force Google to specifically search them using the option site:mail-archives.apache.org/mod_mbox/tapestry-users/ e.g. enter:
Google entry: "T5 update div site:mail-archives.apache.org/mod_mbox/tapestry-users/"
An alternative is to use the archive over at Nabble (it updates almost instantaneously and provides search functionality):
http://www.nabble.com/Tapestry---User-f340.html
Yet another alternative is to use the GMane archive, which goes back much further in time than Nabble.