Unexpected security restriction for a user in both a user and administrative group.

Simple question: is there a document that describes how Windows folder
and file security works for a user that is in both a low-security
group and a high-security group?

I've had unexpected results when I've accidentally grouped myself into
both the local "Users" and local "Administrators" groups. The
limitations of the "Users" group are sometimes enforced even though
I'm in the "Administrators" group.

--ScottS
.