someone mentioned this issue before and i have experienced it myself; you can be editing and previewing a post and suddenly the browser claims it has "expired" and wont show the page.
i'll fix this, i promise.
but until its fixed, a workaround is to just "reload" the page.
it will tell you it must resubmit the page data or something.
then your post will come back, it doesnt get lost(!)
