As for WP 3.9, I came across an article about what is new in 3.9 and comments were showing people having a mix of problems after they upgraded to the new WP. As far as I know, the development team is working on all the bugs people are experiencing; some even lost widgets.
If you can revert back to 3.8.3, you may want to consider that. However, I would also recommend you make a full backup and always when there is a major update to WordPress. Check out the better quality backup plugins.