ANY navigation erases the "Add a Reply to THIS Subject" field, even an imperfect reread of the post. I have lost quite a few typings since the format changed.
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Can you please explain this a little more? Are you saying that if you start entering a message and then click on back and then use the forward button to get back to the message that what you entered disappeared? Or what?
an example:
You start entering a reply and realize that you need to include a link. so you go to the little arrow at the right of the explorer address field and draw and click on the site you want (you can not copy from the address drop down). Then with that page, you copy the web address and click back and Voila! what you typed is gone with the wind.

Also when entering posts and then using back in order to not have umpteen pages hanging you get "this page has expired" which is not really necessary.
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Again, do you mean you enter a message, post it, and then use the back button to get back to where you were? If so, your browser may prevent you from doing this because you may be going back to a form (the message post) that you already submitted.
That is not an issue, although somewhat unpleasant, mainly I added this as "additional information"

Erik