No need to contact the developer since he's sitting right here. There's a reason for this.
Sectiontoggle checks to see if the html element following the header has any text inside it, and if not it doesn't toggle. Otherwise the user would click on that header only to find that it is empty. A header without any text in it is followed by an empty div.
<h1>Header</h1>
<div class="level1">
</div>
The include html follows this empty div.
In addition this lets you create a header which is seen to govern the headers which follow, as for instance an h1 at the top of your page. You can make this a feature request, if it continues to bother you.