Just a comment really rather than a bug - if you accidentally delete a style there’s no option to undo the action. Pay attention because ‘apply’ and ‘delete’ styles are next to each other in the menu.
A small suggestion would be to list the styles in alphabetical order and be able to assign a keyboard shortcut. I find the less mouse usage the better. 
Edit (23 Oct 2013): if you delete the predefined styles and add your own, they are then listed alphabetically. 