Hi fellow DITA users,

We are exploring Oxygen's WebHelp Responsive transformation, so I am exploring DITA-OT chunking to understand how to control the help structure.

I have multiple <bookmap> files referenced from a top-level <map>:


When I publish this (as WebHelp or as plain html5), the <bookmap> levels evaporate and I get a flat TOC of all book chapters:

• Chapter 1
  
  • ...topics...
• Chapter 2
  • ...topics...
• Chapter 1
  • ...topics...
• Chapter 2
  • ...topics...

But what I need is for each book to provide its own navigation level derived from its book title:

• Book 1 Title
  
  • Chapter 1
    
    • ...topics...
  • Chapter 2
    • ...topics...
• Book 2 Title
  • Chapter 1
    • ...topics...
  • Chapter 2
    • ...topics...

Wrapping each <mapref> in a <topichead> creates a level, but that approach doesn't inherit the book title. (Our books are conditional and often have conditional text, references to variables *within* the book scope, etc.).

I looked at the @chunk attribute documentation and experimented, and:

• The to-navigation value sounds like what I need, but it is deprecated.
• The to-content value did create a TOC level named after the book (hooray!), but proceeded to collapse the entire book's contents into a single flat topic (boo!).
• Other values had no effect when applied to the <mapref> element. (Values set on a <bookmap> apply a policy to the entire map, which felt too intrusive to try.)

Books are big, important things. Hopefully there's a way to do this!

 - Chris