:expand-directory will show its children,
:collapse-directory will hide them.
If a child is selected, it'll always be rendered in the list as a child of its parent, however, if the parent is collaposed, only the selected child will show.
:prev-folder with an argument (
-x) to support expanding folders with children while scrolling through the list.
defaults to support nested folders, delimited with
/. IMAP servers which use a different delimiter will be corrected by the worker. Collapsed directories will always show children which are explicitly requested via the
defaults config option.