Hi, I have English dictionary come in default when iBooks was downloaded. Then I downloaded a Chinese dictionary (define, manage, download dictionary) for Chinese books. But then, I found the Chinese dictionary downloaded would disappear after a restart and I had to go thru the whole cycle again. This is really annoying, because I often switch between books written in both languages. I tested this on my friend's iPad air and found the same problem, which lead me to wonder if it is a bug for iOS7. Would somebody test this or offer advice for a solution? Thanks.