How?
Set the entire list as
collapsible
If this option is not displayed, you have not selected all the items in the list or level.
Note If your list contains many items on the same level, each level — including the additional levels below it — will be collapsible if you perform the steps above. In addition, all levels below the original one will also be collapsible.
Set only one level in the list to be
collapsible
Note If your list contains many items on the same level, each level — including the additional levels below it — will be collapsible if you perform the steps above. In addition, all levels below the original one will also be collapsible.
Notes