layer documentation?

[Patrick Gundlach <pg@levana.de>]

Hello Hans and others,

is there any layer documentation out there that I have missed?

I found some fragments in the metafun manual, the details.pdf and
(well, of course!) the source.

Where should the layers be hooked in?

If I say \setupbackgrounds[text][text][background=relpos], the layer
relpos gets repeated; if I use \setupbackgrounds[page][..], the layer
won't be repeated, even if I say
\setupbackgrounds[page][background=..,state=repeat]. (Yes, I know
that I can use \setuplayer[...][state=repeat]; I try to understand
what is going on.)

So should I always use the [page] background to anchor the layer?

Patrick