Hello WayOutWest,
All custom template editing abilities are as they were before. The area that you wished to change is not an editable area for a custom template, notice if you were to save this template and go to use it in a listing, you could have a "Sellers Detail" selected but it would not place the headers for those sections with your details. Anyways, I have made note of the errors and when we jpropagate templates to the live site this will be fixed.