September 6, 2012 at 10:41 am #10366
The syntax can be tricky. It comes from the WordPress query_posts() function. The WordPress codex has some more examples at that link.
I think for what you want to do, assuming the tag you want is ‘mytag’ you would write:
[mashup width="100%" show="query" show_query="post_type=project&tag=mytag"]