will pick up any posts which have the category of “0” checked, which is no posts at all on this site.
display-posts taxonomy=”category” tax_term=”0″
will pick up any posts which have any sub-category of “0” checked, which is almost everything on this site as “0” is parent/ancestor to most of the important categories.
This is not a bug, it is actually quite useful but you need to know the difference!!!
we use display-posts quite happily with up to 6 levels of nesting.
RM April 2017