Monospaced the "Problem" dropdown to vertically align error color boxes

Heya, super tiny pull, but wanted to get started to see if changes were wanted/accepted.

Screenshots attached of difference:
![1387318796](https://f.cloud.github.com/assets/547449/1768886/693a79f0-6769-11e3-94d9-f7640bf24223.png)
![1387318611](https://f.cloud.github.com/assets/547449/1768879/33de1096-6769-11e3-92a2-57033efb04f1.png)