+ 1 David
Lucas you may have a look here to use easily epubcheck (
https://www.mobileread.com/forums/sho...ht=epubchecker) and find epubcheck directly here (
http://code.google.com/p/epubcheck/d...0.zip&can=2&q=). Indeed, with Sigil you will surely be able to find the problem with your TOC (
http://code.google.com/p/sigil/downloads/list).
I'm happy to have both here at the same time, and forgive me Lucas to hijack for a while your post. I don't want to create another post just for that

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David, we had a brief discussion some weeks ago about the Kobo bug with long paragraphs (
https://www.mobileread.com/forums/sho...d.php?t=197956) and I still try (not very hard though) to find a solution about that. A solution is certainly very possible because with the same parameters, if we rename an epub with the kepub extension and set widows and orphans to 0 in the CSS, it works without a hitch. What we have to know is what "kepub" triggers into the Kobo device to solve the problem. Lucas, perhaps you have and idea also?
Anyway, presently I think that this bug is the most annoying of all in the Kobo ecosystem, and thanks for your patience