> According to the specification of XForms, a xforms:model can have
> one or more xforms:instance. I can put one or more xforms:instance
> in xforms:model only if the xforms:model is in the view. Why?
Because if you use the "xforms" attribute on the <page> element
instead, you are runnning the OPS classic XForms engine, which does
not support multiple XForms models or instances.
If you plan to use the latest XForms functionality in OPS, you have to
use the new XForms engine, which requires you to embed XForms models
and instances into XHTML, under the <head> element. This is consistent
with how most XForms engines work.