The version for Moodle 2 works with Moodle 2.1 so no update required. I think your issue could be theme related. Please see attached screen shot of my Moodle 2.1 development with the latest 3rd August 2011 release with the standard theme.
I believe that I will need to do a different version for Moodle 2.2 as there appear to be some code changes that affect it.
At the moment I need to put in the fix for AJAX and update to using Git as a source code control mechanism. Then add in a few enhancements that have been requested. But very busy with my MSc project at the moment so things on hold.
Developer of Collapsed Topics.