A question about FTP, is it normal that I can not create a folder in the root . Creation is only possible in the subfolders. And the root directory (eg web3) is owned by root.
Yes, thats correct and required for security reasons as described in the changelog in the bugtracker. so what you decribe here is not a bug.
A FTP user can store files and folders that are publicly available in the web subfolder and files that should kept private in the private subfolder.