CB

As reported by the Piston, and my analysis:

Thanks for confirming the browser. Actually, it "works" when you click again on the drop-down, then finally the javscript event propagates....

The same is true on all aspects of the user interface. Thus e.g. if you choose different first period, you won't see the extra-fields until you click again on the drop-down...
It is a very old bug from webkit, that I had reported 2.5 years back to the webkit team, and that got fixed in webkit and thus in Safari.

So it looks like Google Chrome is a real fork of Safari, not integrating newer development from webkit....