Argh?
The piv UI is horrible. Sometimes it auto-updates, sometimes it doesn't, the whole open/close item metaphor is horrible as it pushes stuff around constantly, the text-areas are way too small, can't edit your own comments, stuff more or less randomly jumps to other tabs when changing status (which may or may not be currently visible)...
Well, that's just what immediately popped into my head, I'm sure there's more if I look again.
Pivotal has easily one of the worst GUIs of any ticket tracker I have used. It's right down there with bugzilla, just in a different, over-ajaxified way.