CJ20N User Fields tab Restriction

Hi Gurus,

We have a requirement for CJ20N to make some fields in the tab User Fields to be display only as shown below. Users should not be able to edit these two highlighted fields only. I did lot of trial and error but could not restrict these two fields. Can anyone please advise if I need to check any special object which can grey out only these two fields ?

Regards,

Salman