This is somewhat of a new concept in screen doors.  Retractable screen doors are mainly popular when owners have a beautiful doors that lose their appeal when hidden behind a screen.  Carved wood doors stained glass doors, and French doors are good reasons to choose retractable screens. It can be slid to the top or sides of the door-jam, leaving little to detract from the door.  In cooler months when bugs aren't a problem, the screen door may be left retracted.  It may be slid back into use again when the bugs return, or when the occupant wants more airflow.  (note that these are not high security products).