CSS default styles strange behavior when editor is smaller than 768px wide. 

When rendering the CWRC-Writer in a space less than 768px wide, the [style.css](https://github.com/cwrc/CWRC-Writer/blob/master/src/js/lib/jstree/themes/cwrc/style.css) for the jstree library, causes dislay issues. 
![small_editor](https://cloud.githubusercontent.com/assets/487373/4174055/48942162-3575-11e4-959a-d8b2c5e48754.png)