In the example the <ul id="second"> should be 80 px height (2 times the li line-height of 40px), but instead it's 120px. Tested on Webkit Version 5.1.3 (7534.53.10, r107164) and notably Chrome 17.0.963.46
Seems to be fixed as of WebKit Version 5.1.5 (7534.55.3, r112532) and Chrome 18.0.1025.151