Any suggestions on how to persist my selected parcels for Mailing Labels so the Print functionality will work?
Keith, this would be a useful enhancement; please consider adding it to ArcGIS Ideas.
The Public Notification widget was designed to clear the selection when it is closed to make it easier for you to move on to other widgets, but I can see how that choice could be improved.
For now a workaround would be to add the print widget and the public notification widget to different controllers. For example add the public notification widget to an on screen widget place holder and the print widget to the HeaderController widget (based on chosen theme). That way you can have both the public notification widget and print widget open at the same time.
Retrieving data ...