Remove extra spacing below checkboxes filter

Before

![before](https://f.cloud.github.com/assets/25094/1367573/4e6d8dd8-3942-11e3-9b76-f1ae3c09e9e8.png)

After

![after](https://f.cloud.github.com/assets/25094/1367574/9889706c-3942-11e3-9ce3-6dc5c8dc5c3d.png)