I'm having the same problem. Most common occurance is after a post message but it can happen other places too.
I noticed that the blank screen html doesn't start the same as a working page. I thought this might be a hint of the problem.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=windows-1252"></HEAD>
<BODY></BODY></HTML>
</p></div>
