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.
The situation should improve as more and more users switch to SoulseekQt. SoulseekQt supports Unicode, and should allow for searching and file transfer of filenames containing international characters between users of SoulseekQt.
also i.e. scandinavian letters? æ ø å Æ Ø Å
I believe all international characters are covered by Unicode.