Greetings from sunny Singapore .
I just had the same phenomenon, while I was deleting some of my yahoo mails.
The screen got frozen on the last message mail and no matter what , the deleted mail just got frozen and be displayed each time I pressed the mail icon on my IPAD.If the pad is placed via portrait view you can just make out the mail to be read which is obscured by the frozen message. Looks like a common thing happening here, Any way , the way to correct the problem is as shown by Timothy Eskew.
Thanks a heap.