Sibling nodes are not supported
Currently only T-like navigation path is supported: the horizontal line is "sections" (the top level) and the vertical is the path from a section to current document.
This is enough in most cases but in some sibling nodes of the vertical line would be very useful. For example, current position is a blog post, the active section is "Blog" and the whole path looks like this:
( ("Home", "Blog", "About"), "2009", "February", "Some Post" ) }}}
It would be nice to click/hover on "February" and get a dropdown menu with all months; the same with "2009" -- the user wants all relevant years to be listed.
Maybe some more complex controls could be introduced for handling ranges (e.g. "1st week", "low price: $xx..$xxx", etc.).
The problem here is that there can be too many sibling nodes on some levels //or// these levels can be generated (e.g. date parts), so special callbacks for siblings should be introduced. This requires some thinking. =)
A straighforward implementation would suffice to start with.