Autosuggest doesn't overlay the popover properly

Modals are fine, only popovers like share suffer from this.
This only happens in IE9.

![screen shot 2013-06-14 at 16 08 29](https://f.cloud.github.com/assets/218391/654939/0ae51008-d507-11e2-81ce-08b478f6eef2.png)