You probably received pop box asking you to upgrade to Bookshelf 6.7.1, do not do it. 6.7.1 is very buggy. For example, you can not select the definition in the pop up box after you click on glossary, and the text scroll randomly etc. They only thing you get with the new update is the stupid cursor.
Stay on 6.6.3.
Stay on 6.6.3.