In the "Events" section, changing the value to 5/5 results in an empty pie chart, rather than a full one. 0-4 out of 5 all work correctly.

Edit:

The violet 16px 7/7 example in the "Tips" section on the page is also missing.

Browser: Chromium 18.0.1025.151 (Developer Build 130497 Linux) Ubuntu 11.04