Review section 9

All,

1. The text in "9.1.1 The Group Element" says:

    "The author-optional label element has special significance when it
appears as the first element child of group, representing a label for the
entire group."

We might possibly add that an attribute is now allowed as an alternative:

    <group label="Some stuff">

2. "empty sequence" / "an empty sequence" → "the empty sequence", for
grammar and consistency:


https://www.w3.org/community/xformsusers/wiki/index.php?title=XForms_2.0&diff=258&oldid=254

3. I am suggesting some changes here to specify what happens when `caseref`
attribute does not point to a node:


https://www.w3.org/community/xformsusers/wiki/index.php?title=XForms_2.0&diff=259&oldid=258

4. Speaking of `caseref`, I don't remember if I raised this before but it
is limiting to depend on the `id` of the `<case>`. In our implementation,
we added an optional `value` attribute on `<case>` which can be used to
associate a value with each `<case>` element.

-Erik