displaying last leaf of doc in chm file using htmlhelp

Hello all
I am using the htmlhelp stylesheet to create the chm version of my documentation.
A test file looks like:

<?xml version="1.0" encoding="UTF-8"?>
<?asciidoc-toc?>
<?asciidoc-numbered?>
<article xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en">
<info>
<title>Documentation</title>
<date>2015-07-13</date>
</info>
<section xml:id="_chapter_1">
<title>Chapter 1</title>
<section xml:id="_section_11">
<title>Section 11</title>
<section xml:id="_sub_section_111">
<title>Sub section 111</title>
<simpara>Some text appears here</simpara>
</section>
</section>
</section>
</article>

I am chunking this file with the following parameters:
use.id.as.filename=1
chunck.section.depth=3
chunck.first.sections=1
I order to have seperated files for the different contents.

Now when I open the chm file I would like NOT to display on the right panel the "empty" content of Chapter 1 and Section 11 while keeping them appearing in TOC. That is display only the final leafs containing "real" content.

Is there a trick/parameter to do that (NB: my "final" leaf is not always at the same level)

Thank you for your help !

Jacques