>Hi Michele
>
>I'd like to ask why insert mode changes to overtype at some point in the original typing of, or the editing of a message.
>
>It often happens when you go back to the middle of a section of text in order to insert some extra text. You look up from the keyboard and find that you've typed over much of what was already there, rather than adding to it. Very frustrating and annoying.
>
>I can't see any reason for this (and it's not cos I've hit the INSERT key)

Yes, I've seen that too, and even though I haven't hit the Insert key, so far it's always been because I've hit the Insert key. ;)