As of Chrome v32 (the version where they changed the visual design and added the skinny scroll bars), so people may have trouble using things like drop down menus. The temporary fix (until Google patches chrome) is to:
Right click on the Chrome icon, go to Properties, then go to Compatibility, and check "disable Visual Themes". Close ALL Chrome windows and start a new one and it should then work.
Please note that this may affect sites other than BoL and is not caused by BoL nor is limted to BoL.