In Version 19, we introduced a new feature called "expandable regions". When activated on a top-level table, this will enable to dynamically collapse and expand the table's sub items in the preview and HTML5 viewer.
So far, it hasn't been possible to export to all of our export formats from the preview window. The simple reason is that we're using the EMF file format internally while the exporters need completely different information that cannot be extracted from the EMF. Thus, we were only able to support image file formats and - of course - PDF, which is created from EMF vector information.