I've found a few more issues with the new tab support - changing Look and Feel caused startup problems, and you could get errors when clicking near (but not on) a tab. There were a few other things as well - an update is available in the dev level updates. bear in mind, if you don't have the latest dev updates (with tabbed browsing), this is all something you can ignore for now.

I also fixed a browser launch bug on Unix/Linux. In some shells, urls with ampersands were being taken badly - the ampersand being seen as a request to background the task rather than as part of the url. I fixed that, and the person I tested it with reported that it worked just fine.