global layout change from header=none in \setuphead

[Sanjoy Mahajan <sanjoy@mrao.cam.ac.uk>]

Another of those 'not sure if I'm confused' examples:

\setuphead[title][header=none]
\starttext
\title{Hello}
\dorecurse{15}{\input tufte}
\stoptext

With header=empty, it worked as I expected: The first page had no page
number in the header and the other pages had a page number.  Then I
tried the example above, with its header=none, so that the first page
would allocate no space for the header (as well as have no page number).
But then no pages, not only the first, allocated the header space.

Is there a subtle difference between header=none and header=empty making
the first one a global setting but the second one local to the page with
the title (the local behavior is what I had wanted)?

It's probably a related confusion or bug, but an alternative solution
(from <http://www.ntg.nl/pipermail/ntg-context/2005/009180.html>) using
\definelayout[1] also produced a global layout change:

\definelayout[1][height=7in]
\starttext
\title{Hello}
\dorecurse{15}{\input tufte}
\stoptext

This is all with ConTeXt ver: 2006.10.24 13:47 (same results on the live
context).  Any hints appreciated!

-Sanjoy