Thanks for your suggestion and fix! Actually I am creating epub by editing a template I found online, which links to nav from nav.
Here are possible solutions:
- Link to # (using Sigil from master branch). This is not supported in some viewers.
- Link to #nav. This is not supported in some viewers.
- Create a separate HTML Table Of Contents. This is a good solution, but I have to look into css used by nav.xhtml to make separate HTML Table Of Contents looks pretty.
- Remove link to TOC or nav. The link doesn't seem necessary to me.
My conclusion is that I will try solution 3 first, if this looks like too much work for me, I will use solution 4.