Using IE9 specifically I cannot expand the task output using neither the ± expanders nor the Expand/Collapse all buttons. It does work in Chrome and Firefox (later versions). Someone also reported to me that they don’t work in FF 3.6 (not a big deal) which may help diagnose what functionality is not present.
I’ve found a similar issue with IE9, but it goes away if I refresh the page. I think the script may not be loaded on some occasions. I’ll try and include a fix in the next release.