Spring-Loaded Folders in OS X Yosemite
A spring-loaded folder pops open when you drag something onto it without releasing the mouse button. Spring-loaded folders work with all folder or disk icons in all views and in the Sidebar in OS X.
Here’s how spring-loaded folders work:
Select any icon except a disk icon.
The folder highlights to indicate that it’s selected.
Drag the selected icon onto any folder or disk icon — but don’t release the mouse button.
You’re hovering the cursor over a folder or disk icon without releasing the button.
In a second or two, the highlighted folder or disk flashes twice and then springs open, right under the cursor.
Press the spacebar to make the folder spring open immediately.
After the folder springs open, perform any of these handy operations:
Continue to traverse your folder structure this way. Subfolders continue to pop open until you release the mouse button.
If you release the mouse button, the icon you’ve been dragging is dropped into the active folder at the time. That window remains open — but all the windows you traversed clean up after themselves by closing automatically, leaving your window clean and uncluttered.
If you want to cancel a spring-loaded folder, drag the cursor away from the folder icon or outside the boundaries of the sprung window. The folder pops shut.
After you get used to spring-loaded folders, you’ll wonder how you ever got along without them. They work in all four views, and they work with icons in the Sidebar or Dock. Give ’em a try, and you’ll be hooked. You can toggle spring-loaded folders on or off in the Finder’s Preferences window. There’s also a setting for how long the Finder waits before it springs the folders open.