I'm trying to track down WHY I can write in a folder that, by my best estimation, I should not be able to write. The folder is shared with "Everyone" has "Full Control", with the files being more restrictive. My best guess is there's some sort of sub-group membership that's allowing me to write, but the nesting of groups that exists in our Active Directory is pretty extensive.

Is there a tool, that will tell me which of the ACL entries allowed or disallowed my writing a file in a folder?

The Effective Permissions dialog is marginally helpful, but what I need is something like a "NTFS ACL Trace Tool", if such a thing exists.