Sigil doesn't have any inherent features that would affect hyphenation. It's a question of css and the rendering engine being used to display the ebook. I saw in your original post that the hyphenation is needed in the resulting kindlebook created from the epub.
In that case, you'd probably be better served asking the question in the Kindle forum. Something to the effect of: "is there anything I can do to my epub to ensure hyphenation in the resulting kindlebook?"
|