Managing dock with WGM

10.5.2 server OD/AD integration. My AD groups are a member of an equivalent OD group which has managed settings applied. I can't seem to correctly manage a user's dock. The managed settings get applied, but the user still gets their own dock items as well which they can remove and add to. The option for merge with user's dock is unchecked. I know I could probably manage the whole com.apple.dock.plist file, but I am trying to avoid that. Any ideas? Maybe this is intended behavior, but it seems to me like the merge with user's dock option doesn't work as it should.