I had hoped to be able to refine the output filtering by combining a category and tag slug ie cat=A tag=A1 would only show posts in cat A tagged with A1. What I'm finding is though that the tag slug doesn't work at all. Using cat A and tag A1 returns a whole bunch of posts not in cat A or tagged with A1.
I tried adding "AND" but that didn't work either.
UPDATE:Never mind - WP was adding
<code> tags and messing up the shortcode!