Fix column width in Firefox

It looks like part of the issue might be that we are using webkit specific scrollbar changes. (I looked, you can't do that in firefox.)

![screenshot from 2013-09-19 11 32 53](https://f.cloud.github.com/assets/1002908/1174540/3f453312-2149-11e3-99b4-1d63cf3a9178.png)

<!-- TRESTLE
{"columnWeight":0,"milestoneWeight":708}
-->