In lesson with matching question, detailed statistics beneath the reports tab is broken. No data is returned. Tested on 1.8.2+ updated from last Friday, 10/05/2007. With debugging turned on we see this error:
XML Parsing Error: no element found
Location: http://moodlesite/mod/lesson/report.php?id=38&action=reportdetail
Line Number 173, Column 1:

To reproduce:
1. Create a lesson and add 1 matching question.
2. Have a student complete the lesson.
3. Go back to the lesson as a teacher and click the reports tab and then detailed statistics.

To see the correct behavior, repeat the above, except create a lesson without any matching questions