minimum height to keep border from falling under button

Border on view sometimes appears underneath view.

![screen shot 2014-11-21 at 3 14 32 pm](https://cloud.githubusercontent.com/assets/6811459/5148901/9727001c-7191-11e4-951f-1b279cb5e1cd.png)

![screen shot 2014-11-21 at 3 13 52 pm](https://cloud.githubusercontent.com/assets/6811459/5148909/b33c615c-7191-11e4-8a5c-c13a05ecd1eb.png)