Hi Adam,
 
I am already using your latest build and already had tested it on your own demos. According to my user experience the normal behavior of a drop down is first to click the drop down to fall and then to click some element of its content. I don’t think that this is the behavior of your demo under Firefox currently. The only way in which I can select something under FF is to MouseDown the drop down list to go to the appropriate element and then to MouseUp on it.

Thanks,
Vesko Kolev