"Add group" is cut off when the translation is longer then the longest group name

@jancborchardt @MorrisJobke 
![group-add](https://cloud.githubusercontent.com/assets/213943/7409181/7fda0038-ef24-11e4-9cda-f24b977e33e5.png)

Related #15819 #15820 
