I am creating a new issue for this, as requested by Petr Skoda.
There are still issues with the new editor toolbars when editing questions. Try, for example, editing a muliple choice or numerical question.
I am seeing this with Ff (25.0), Chrome (30.0.1599.101 m) or IE (10.0.9200.16721), and currently I am using theme Anomaly. The editor does not fit inside the fieldset, and the right hand side is cut off (so you can't scroll or resize.)