Usage of SELECTION-SCREEN COMMENT FOR FIELD!

Below code is used to emphasize the important use of FOR FIELD Addition to the SELECTION-SCREEN COMMENT statement.
SELECTION-SCREEN BEGIN OF BLOCK B1 WITH FRAME TITLE TIT1.

SELECTION-SCREEN BEGIN OF LINE.

SELECTION-SCREEN POSITION 20.

PARAMETERS P1_MATNR LIKE MARA-MATNR.

SELECTION-SCREEN COMMENT 1(12) COM1 FOR FIELD P1_MATNR.

SELECTION-SCREEN END OF LINE.

SELECTION-SCREEN END OF BLOCK B1.

LOAD-OF-PROGRAM.

TIT1 = 'Selection-Criteria'.

COM1 = 'Material No'.

Output:

F1 help for the field MATNR will be displayed both for the input field(P1_MATNR)  as well as the comment(COM1).