so, I was having a terrible 'disappearing page' problem when converting a epub to mobi.
the thread is here:
I am posting here, because I think the solution to the problem indicates a... i don't know... it's either a very minor bug in Sigil, or just a mistake in the official tutorial... or something. I figure some of you experts can take a look at it and decide if it's worth dealing with.
Anyway, the problem ended up being that when you create a cover using the directions in the tutorial, the cover page 'steals' the header/title declaration of the page you split it from.
I have replicated this to make sure... but yes, when you insert an image, then do a chapter break... the 'new' cover page grabs the header. I can see this being 'not a bug', but in that case, someone really should update the tutorial because it's cost me hours to figure this goofy little problem out.
This then breaks conversion to Mobi, at least, using Calibre, and causes your first section following the cover to no longer appear using a Kindle.