[davidfor]

Originally Posted by fdanis

Afaict, looking at the epub file using "E-book Editor", there's only one heading level.



This is reproducible with www.ebooksgratuits.com/epub/zola_germinal.epub.
I'm using version 4.19.14123

I did some testing after my post earlier, and this book confirms it, the problem is when the the ToC entries have fragments in it. With this, the graph shows the empty bar plus the proper one. Removing the fragments, which aren't needed in this case, and the graph becomes correct.

What I mean is, in the toc.ncx file, it has the following:

  <navMap>
    <navPoint id="PREMIÈRE PARTIE" playOrder="1" class="">
      <navLabel>
        <text>PREMIÈRE PARTIE</text>
      </navLabel>
      <content src="book_0001.xhtml#auto-toc0"/>
      <navPoint id="I" playOrder="2" class="">
        <navLabel>
          <text>I</text>
        </navLabel>
        <content src="book_0002.xhtml#auto-toc1"/>
      </navPoint>
      <navPoint id="II" playOrder="3" class="">
        <navLabel>
          <text>II</text>
        </navLabel>
        <content src="book_0003.xhtml#auto-toc2"/>
      </navPoint>

The fragments (marked in red) in the links are the trouble. As the target is the first tag in the each file, they aren't needed. You can edit them out manually, which is what I did to test. Or, use the ToC editor in calibre to regenerate the ToC based on major headings. Sigil should have a way to do it as well. Then remove and resend the book and it should be OK.

And, as it is a bug in the firmware, I recommend reporting it to Kobo. I will, but, it might be a couple of days before I have time to.