For numbered data, the line command field displayed to the left of each line duplicates the sequence number in the data. Normally, the editor automatically scrolls left or right to avoid showing the data columns that contain the sequence numbers. However, you can explicitly scroll left or right to display the sequence numbers. The DISPLAY operand of the NUMBER and RENUMBER commands also causes the editor to display the sequence numbers.

For example, assume that the data has COBOL numbers in columns 1 through 6 and the number mode is NUMBER ON COBOL. When the data is displayed, column 7 is the first column displayed. If you change number mode to NUMBER OFF, the data is scrolled so that column 1 is the first column displayed. If you then change number mode to NUMBER ON, the data is scrolled back to column 7. But if you change number mode to NUMBER ON DISPLAY, the sequence numbers in columns 1 through 6 remain displayed. The sequence numbers in columns 1 through 6 become part of the data window, but cannot be modified.