NTFS permissions, real time ?

Hello all,

I've a problem on my Windows infrasctructure.

I've two Windows Server 2008R2 which are File Server.

The first is the principal File Server, with file shares.

The second is the rescue File Server.

I used DFS to replicate permanently content of File Server1 to File Server2 (ie, I don't use Namespaces, just replication).

I see a behavior, that is (for me) abnormal when -> ADD/REMOVE/MODIFY NTFS permissions on a share.

When I add a group on a share (NTFS permissions), the users which are on the group must close and open again their windows 7 or windows 8 session to see new NTFS permissions applied. So, this is not in real time ? I'm confused.

When I add not a group, but directly an user, the users have immediatly good rights., without close/open their session.

Can anyone help on this subject ?

Thanks