I could not find this information in the help file or on the CocoaTech forum. If you use CocoaTech's Path Finder, the Finder replacement that has a lot of extra functionality that is missing in the normal OS X Finder, you may be browsing around in a folder with many subfolders, and wish to somehow "collapse" the folders you opened, to clean up the view.
Clicking the disclosure triangle of 100 open subfolders is rather tedious, so isn't there an easier way? I stumbled on a method. Here it is.
How to Collapse All Subfolders in Path Finder
- In list view, select all. Command-A.
- Press Option-Left Arrow.
- Sit back, amused, but don't do anything boneheaded like pressing Command-Delete.
And voila! Collapsed folders.