Is it possible to see debugging blocks only for specified role?

I made special role "theme developer" to see debugging blocks of Omega only for this role. When I check in admin/appearance/settings/my_subtheme -> Debbugging options:

  • Enable the debugging (placeholder) blocks for the selected roles.
  • Enable the grid overlay for the selected roles.

and select "theme developer" role debugging blocks will be seen by granted users only.

If I am an administrator I can see debugging blocks even if I'm not in "theme developer" role. Why?

After documentation it should work as I wrote in idea but it is not.