I have just PM’d you because I can’t share the form on here, but what I can tell you is that when the user clicks inside the section, the text adds to the insertion point and doesn’t replace the full section’s text.
I don’t know anything about XML mapping, but the document already came to me with some content control boxes in. I added an XML map of my own which is working very well, but I wondered if that has messed up the other, original content control boxes? Am I being naïve with that question?