A bug with the "Book and Quill" (if you type "A" it erases everything.)

Dear Mojang,
I have been having a problem with the item "Book and Quill". It works if you type in it but if you type the letter "A" it erases everything that you have already written. I really like to type in books so this would be great if you could fix this. And please if anyone else is having this problem please tell me. Thank you. -Dominic C.