The folders are organized in a tree structure: this is purely for the convenience of the user, so any folder may contain as many other folders as needed. Folders can be managed either from the top level menu or from the popup menu in the folder control invoked by pressing the right mouse button in it. You can group folders together by making the sub folders of another folder. This builds no physical connection between the folders but makes the sub folder inherit certain configuration defaults settings from their parent folder. We will soon add a ``folder group'' folder type not representing any mailbox but just being a group of folders.