Working on our soon to be launched intranet and I have added some html 5 elements. ie defaults to ie7 standards when viewing a vibe site meaning it doesn't render html 5 stuff correctly. I put in a line of code to force it into standards mode
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
in the jsp file and found out later that in this mode when I try to submit a discussion entry I get this message (and this only happens in ie, version 8,9,or10 and you can test this simply but hitting f12 in ie and change to standards mode in a vibe site, no need to mess with include.jsp to see the behavior)

HTTP Status 404 -
type Status report
description The requested resource () is not available.
Apache Tomcat/6.0.35

I downloaded chromeframe and that worked fine, but the groupwise client vibe viewer doesn't seem to be able to use it.

So if any of the following can be solved I would be in business
Figure out why standards mode breaks discussion submission or
have groupwise use something besides ie as its integrated vibe viewer