CHECK ALL FILES: This item does just what you’d think: it puts a checkmark next to all files (and folders, if that Preference is on).
UNCHECK ALL FILES: The opposite of the above; it removes the checkmark from all files and folders. This is useful if you want to restore only a few files; start by unchecking everything, then check those files you want to restore.
OPEN ALL FOLDERS: This item opens all the folders in the File List, allowing you to see all the files in the BackupSet.
CLOSE ALL FOLDERS: The opposite of the above; it closes all folders.