Fixing an issue where you cannot click a link directly above the nub

[mcicoria]

If your target element is clickable, like a link, you cannot click directly above (below, left of, or right of) the nub. It's a small area where the transparent top (bottom, left, right) border of the nub is overlaid on the element. It's a small change, but it fixes it.

Here's a gist to recreate the issue: https://gist.github.com/mcicoria/6094454

Here are the before and after shots of the borders that were transparent at #f00:

[mrsweaters]

Thank you!