Instead of drilling down to a blank diagram you can import (copy) an entire map of diagrams as a drill down. Select Drilldown-Import. Then select the map you want to import from the list. This list is of the maps in the current Space and in cludes maps that are in the Deleted folder. You can filter on the list.
When you select IMPORT it will COPY all the diagrams in the selected map (the entire structure) as a drilldown.