If I go into HTML mode to edit things, and then go to NORMAL mode and hit UNDO, it replaces all of the content in normal mode with HTML. Since this is in normal mode, this HTML, of course, ie actually text with escaped entitiies.
So, I then have to go into normal mode, select the text, go into HTML mode, paste it back in as HTML and I'm back to where I was. Not a HUGE deal, but I can see this being a major issue for those not in the know.
May I suggest that you disable the UNDO function if the very last function was a switch to normal view?