Restrict planning folder in display mode only.

Hi all,

I have restricted the folder under R_PM_NAME with display mode only. The situation now is that i would like to restrict some of the authorize user to view or display the folder contents only instead of display and edit the contents. But after i have applied the display mode only for the particular folder, the user still can display and also edit the contents. Anybody knows how is the way to restrict the folder for only display mode? Very much appreciated for looking into this issue.