Thanks for the investigative report, Madeline. I appreciate the explanation. The new format seems to act a bit odd at times, especially if you paste some altered text into the window. The main problem is that you can't see where the modifiers are so sometimes you end up with 'junk' ones hiding and messing me up. (The same kind of thing happens often in simplified HTML editing programs if nobody checks over the raw code afterwards.) I'm also not seeing a cursor consistently either - there seems to be a weird bug with that. I suppose the toggle button will help with most of this but I might want to have a user preference available to lock it in the old mode.
EDIT: Another weird bug I found - if I have an emoticon at the end of the text and then I switch modes twice it adds a space at the end.