A pop-up menu in the Dock offers you the same type of hierarchical submenu structure that was available in the Apple menu of Mac OS 9 and earlier. To create a pop-up menu in the Dock, simply drag a disk or folder icon into the Dock, between the dividing line and the Trash. Disks and folders in the Dock must be placed to the right of or below the divider.
A disk or folder in the Dock reacts two ways:
1. When clicked, the item opens in a Finder window.
2. When Control-clicked, a pop-up menu with submenus appears. With a disk or folder in the Dock, you can use submenus to navigate through folders to a file.
Figure 1 Navigating a disk from the Dock