A family of Microsoft word processing software products for creating web, email, and print documents.
This is happening to me too. I'm running Word 2010 64 bit (v. 14.0.6112.5000), Windows 7 x64. It seems to happen when I am editing a comment in print preview mode, and pause typing for a minute or so. Then, boom, it switches to draft mode.
Oddly, I don't remember having this problem before, so it is likely specific to the document I'm working on. The document comes from someone who is using an earlier version of Word, but I saved it as a Word 2010 document.
Microsoft, please fix!