earlier versions of thunderbird only allowed a folder structure containing inbox as folder, and all other folders as subfolders (see screenshot of folder 1).
newer versions of thunderbird changed this folder structure, so inbox folder is on the same level as other folders (see screenshot of folder 2).
how to change this and unify the folder structure of all my old and new email accounts (all of them are IMAP-accounts on the same web server, i.e. two folder structures possible on the server)?
