Minor Currently NParser supports "data_exists" parameter to be passed to "m_RenderElement" and "m_Include" tags. When there is no useful data (none of "Field" tags were called) in block parsing result or after template inclusion, then nothing is shown at all.
When tag "st_ContentBlock" has output, then NParser don't know nothing about that and still shows no data, when "st_ContentBlock" tag is inside block/template, that is rendered/included using data_exists parameter.