Returning to Edit after Preview loses post contents

If I press the "Preview >" button then return to amend my post with the "< Edit" button, the content of the post is lost. The text editor contents are the same as when I started my post: either nothing (when creating a new post) or just the full quoted text (if I quoted another post).

Latest IE version on Win XP, behind SBS2003 ISA firewall.

[351 byte] By [StevenKelly] at [2008-2-1]
# 1
We've gotten a few reports of the edit interface losing content but it seems to come and go and is not consistantly reproable. Going to have to look at this issue a little closer.
LisaAmblerMSFT at 2007-8-21 > top of Msdn Tech,Feedback for forums and MSDN websites,Bug Reports for Forums website...