The Contours in the job section lists the recognized contours in the file.
By default, all available contours will be cut. To enable a specific contour only, select that contour from the list. To select more than one contour use the Ctrl key.
Select all contours: removes selected contours in the Contour in the job list and enables all available contours.
Info
When all available contours are selected, they do not appear highlighted.