[NTG-context] Why do margins bleed?

I have been playing with the very interesting t-layout module written by Patrick Gundalach. When looking at the visualization thus presented I have these questions: 1. Why do the left and right margin areas bleed off the page? 2. Why are the margins offset a little from the main text block? These offsets are defined as leftmargindistance and rightmargindistance. These aspects seem to be related. . -- John Culleton Able Indexers and Typesetters http://wexfordpress.com