Bob is correct, nested collections don't get saved, just articles in
that collection you initiated the download from. Nesting in our system
is pretty flexible and invoking a massive download could creates data
and storage issues on the device that we want to avoid.That said, some
early thinking is going on about how we might address the exact use case
you are concerned with, which isn't user triggered, but instead some
automatic downloading and persisting of content in the project.