1. <xsl:apply-templates select="current-group() except blah"/>

still applies templates to blah

2. If your group by patttern evaluates to  an empty element
current-grouping-key() will yield nothing. However one may (as I did)
want to get at the attributes of such an element but this is not
possible.

3. If you group-starting-with it's weird to then see things not
encompassed by the starting-with expression appear as a group because
they precede the first occurrence of the starting-with expression.
While this works as specified  because for-each-group is a total
function over the population it does result in a mismatch between the
grammatical semantic and the exhibited behaviour, or to put it another
way it does what it says in the spec but  doesn't do what it says on
the tin.

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