Open or Close All iTunes Playlist Folders

The secret shortcut to open or close all iTunes playlist folders in a given window is to Command-Click on one playlist folder’s disclosure triangle icon.  This will cause ALL folders to perform the action that a normal click would. 

So if the folder you’ve clicked is open, a command-click will close all folders.  If the folder is closed, a command-click will close all folders. 

This is great when you want to clean up your sidebar view or when you’re picking songs to sync from within the iPhone settings screens (where all the folder lists are expanded by default).

This trick also works in the Mac Finder, but the normal Apple convention is to use an option-click.