Atril shows just fragments of ePub book

[psl]

Ubuntu 16.04.5 i386
atril-1.12.2-1ubuntu0.3

I noted that just few chapters from ePub book are visible when opened in Atril. For some unknown reason (a bug ;-) only several chapters from the ebook are visible.

The source of the ebook (Perl tutorial in Czech language); book can be downloaded for free.

https://knihy.nic.cz/files/edice/perl_pro_zelenace.epub

The same book in PDF, a reference for troubleshooting
https://knihy.nic.cz/files/edice/perl_pro_zelenace.pdf

When the epub book is opend in Atril, it shows that book has 59 pages and it shows just several "paragraphs" from each chapter. That is just a small fragment of the whole book.

You can open the same epub book with Sigil and you will see how much more text is in the book. Or compare with pdf version of the book.

[psl (slansky)]

I guess that Atril cannot handle several levels of "ul" lists in the toc.xhtml file, structure is like this:

$ xmlstarlet elements toc.xhtml
html
html/head
html/head/title
html/head/style
html/body
html/body/h2
html/body/ul
html/body/ul/li
html/body/ul/li/a - visible
html/body/ul/li
html/body/ul/li/a - visible
html/body/ul/li
html/body/ul/li/a - visible
html/body/ul/li
html/body/ul/li/a
html/body/ul/li/ul
html/body/ul/li/ul/li
html/body/ul/li/ul/li/a - visible
html/body/ul/li/ul/li/ul
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li
html/body/ul/li/ul/li/a - visible
html/body/ul/li/ul/li/ul
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
html/body/ul/li/ul/li/ul/li
html/body/ul/li/ul/li/ul/li/a - HIDDEN, a bug
...