[santosha]

My book contains both parts and chapters (2 levels deep) and when automatically generating an NCX file with Sigil, this gets reflected in a 2-level NCX file with NavPoints nested within NavPoints.

Now, I've read various sources online that indicate that Kindles do not support nested NavPoints in NCX files and am a bit confused as to what exactly "not supported" means, if these sources are correct. (Can't find anything in the official Amazon guidelines about it)

When playing around in the Kindle Previewer with my test-file (with nested NCX, two levels deep) the NCX file shows up in the NCX previewer as nested and working fine (to expand with the plus sign and see all points). Further, when previewing the file on my physical Kindle PW the nested NCX seems to be working fine, with two levels under the "Go To"-button, showing the parts and the chapters contained within them. The "Reading time left in chapter" on the PW also seems to be correctly reading all the points.

The only time it seems to me that the nested NCX is not playing nice is that the chapter markers on the progress bar of the regular Kindle and DX in KP only show markers for the Parts, not the chapters--so I'm guessing this is what the talk about "not supported" is about?

Would you recommend I simply "flatten" the NCX generated by Sigil (which is kind of nice--I like the nested "Go To" menu on the PW) to maximize compatibility and as a best practice? Any other advice in this matter? What is stylistically recommended?

Many thanks in advance!

Santosha