I started seeing this on the 3/11 build. Reply to a message. Instead of having the caret above the line that says "Scott Putterman wrote", the quoted text is now at the top of the body and the caret is placed within the quoted text. So, if you start typing, you are typing in the quote. This makes it hard to use reply.
I *think* this might be related to the recent forward/edit as new/template horkage found in bug 130103. Some HTML controls are passing null.
I can confirm this is a side effect of bug 130103. The potential fix I posted in bug 130103 fix this problem as well. *** This bug has been marked as a duplicate of 130103 ***