Please see this thread here:Problems with ESV
As I understand the above thread this is by design? Doesn't make sense to me at all this is not how the PC version works. Note that the cursor becomes a hand icon (why if its not clickable?). When you click the link/footnote in the mac ver nothing happens... On the PC version when you click the footnote the refs become hyperlinks which are then clickable. Very nice, this is how it should be.