You're probably panicking...don't! We can get this back for you. Just follow these steps:
So you accidentally deleted your "Roof" Section from your Residential report...Click "+Section" at the bottom of the Section column (this applies to items and comments too depending on what you deleted).
In the window that pops up, Select "UNDELETE SECTIONS" > Check the box next to the section you want to recover > Select "UNDELETE SECTIONS".
Your "Roof" Section will now appear back in your Sections panel. Be aware that you have this option in your report writer, but NOT IN YOUR TEMPLATE EDITOR. Be careful in there!