One small thing is that the default size of the -/+ toggle buttons is really tiny, making it tough to press them (And their style is hard to override, since they have a lot of inline styling applied via the library) Maybe replace them with "[-]" and "[+]" for more clickable area.
One more suggestion: It would be cool if clicking on an entire item could collapse/expand it, not just the +/- symbols. Then the size of the +/- would no longer be an issue.
From: https://groups.google.com/forum/#!topic/clojurescript/6B68zEij6Bg