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

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:

![Before the changes](https://f.cloud.github.com/assets/1305676/866680/bc90faec-f6a4-11e2-9a81-1fd34e6f1df2.png)
![After the changes](https://f.cloud.github.com/assets/1305676/866681/eda0bf00-f6a4-11e2-8066-d7a4b42abbfb.png)