Close button sends client to the tray, statically linked Qt for OSX.
See the Changelog for list of features and fixes currently only available in the nightly builds.
I seriously need a break from development, so I figured I'd release what I have so far as public build 2. The biggest change is the addition of user groups; the ability to assign one or more groups to users on your list, and share different folders to each of those groups in your file sharing settings. The client also seems to now be able to return downloadable search results. Everything else is relatively minor:
Hopefully nothing's gotten worse since the first build, but there's been some major overworking in the area of uploading so new bugs are possible. If anything glaring comes up that wasn't there in the first build I'll update build 2 as soon as possible.