removing "min-height: 80px;" from class label

the css-class label is used in the fields section of the table panel. checked fields currently have a 80px rectangle around their names.


![screenshot from 2014-01-02 14 19 21](https://f.cloud.github.com/assets/707739/1832333/903d6a50-73b0-11e3-8eeb-c869c28a562e.png)