Summary: Report bugs in Channel 9
Nearby: BugsFixed, FeatureRequests

v4Bugs - For reporting bugs in c9v4

You can also post your bugs and feature requests to the Known Issues forum thread

Are you actually asking for FeatureRequests? Has one of the BugsFixed come back? Or are you seeing RenderingBugs with a specific browser?

Otherwise, if something's not working as it should, pick the right place to report it:
*ForumBugs - bugs that only affect the forums (see also ForumRequests)
*MoblogBugs - bugs that only affect the moblog (see also MoblogRequests)
*RSSBugs - bugs that affect RSS aggregation
*SiteBugs - bugs that affect the entire site (see also SiteRequests)
*VideoBugs - bugs that only affect the videos (see also VideoRequests)
*WikiBugs - bugs that only affect the wiki (see also WikiRequests)