Given the following document:

Heading    (<-- Formatted as heading1)
Contents   (<-- Formatteed as oridnary text)

When a range is around both lines and the document is being saved as DocBook
XML, you get

<articleinfo>
<title>Article Info Title</title>
<subtitle/>
<edition/>
</articleinfo><sect1 id="TitleOfSection"><sect1><title>Heading</title>
<para>Contents</para></sect1>
<para>Contents</para>
</sect1><para/>
</article>

Ay you see the line "Contents" is doubled. Then the range is only around  the
Heading line, the result is 

<articleinfo>
<title>Article Info Title</title>
<subtitle/>
<edition/>
</articleinfo><sect1 id="TitleOfSection"><sect1><title>Heading</title></sect1>
</sect1><para>Contents</para>
</article>