It very well might be your IE. I know DW is supposed to play nice with all browsers, but IE is infamous for messing with sites that should run fine. If it keeps up, my only suggestion is to file a support request. They've always been incredibly patient and good about working with users to help figure out what's wrong. It's one reason I love it here so much. *shrugs* But you sound like you know what you're doing, so maybe you'll be able to figure it out.