Directory and Resource Administrator 6.x
Assistant Admins can see the Configuration snap-in node in the Directory and Resource Administrator MMC.
If the Assistant Admin is part of the Domains Admins group or is a local administrator on a member server that DRA is managing, then the Assistant Admin is automatically included in the Assistant Admin group Built-in Domain Admins. The Built-in Domain Admins are automatically delegated certain powers in DRA and are automatically added to certain ActiveViews. One of those ActiveViews is the Built-in Configuration ActiveView which covers all objects in the domain that affect the configuration of the administration server.
This is by design of the product.