Answer: You can restrict a user from using page up and page down in the following manner…
- Go to Main > Master Data Management > Others > Designation Set Up (M > O > D)
- Open the list by pressing the keys Alt+L.
- Select Designation name
- Set “Change Action Control=Yes”
- Set “Allow Page Up/Down At Transaction=No”
- Set “Allow Page Up/Down At Voucher=No”
- Save.
- Save.

For more details please visit: http://www.rancelab.com/help/fr6_designation_setup.htm