[NTG-context] \but command for referring to index.

The useful d-en-all.tex example shows buttons used for accessing Acrobat Reader functions and also for jumping to the Contents page. I would like to create a button that would jump to the back-of-book index. The info in the manual is a bit terse and I don't quite follow it. also, I read posts referring to a \button command. How does this differ from the \but command? Thanks for any help! -- John Culleton Able Typesetters and Indexers http://wexfordpress.com