HEIDENHAIN iTNC 530 User Manual page 534

Switch the frame overlay display for the workpiece blank on/off:
U
Shift the soft-key row until the soft key for the rotating and
magnification/reduction appears
U Select functions for rotating and magnifying/reducing:
U
Show the frame for the BLK FORM: Set the highlight
in the soft key to SHOW
U Hide the frame for the BLK FORM: Set the highlight in
the soft key to OMIT
534 Test Run and Program Run