The Dock in OS X is a convenient location to store commonly-used applications, as well as links to favorite folders that can be opened as stacks. In addition, it contains any windows that you have minimized, along with the omnipresent Finder and Trash icons for easy file management.
Despite being useful, while you can organize items on it and resize them to your heart's content, the Dock is missing a simple way to separate various items you place on it. The one separator the Dock contains is useful for manipulating the Dock, and separates applications from other items you may wish to place on the Dock, but you may wish to have additional separators to better organize collections of items on the dock. For instance, having Office-related programs slightly detached from system utilities may be a nice touch to implement.
One way to do this is to add a spacer or two to the Dock, which can be moved around and placed between programs to help group them. There are a number of third-party utilities that will do this to some degree, but it is also relatively easy to do this using Apple's built-in programs and services.
The approach simply involves creating a fake application in the Finder, and then replacing its icon with a transparent image, which can be done by the following procedure:
Step 1: Create and copy a transparent image to the clipboard
- Press Shift-Control-Command-4, and then click and drag to take a selection screenshot that saves to the clipboard.
- Open Preview, and press Command-N to create a new image from the clipboard contents.
- Now press Command-A to select the image, and press Delete to clear the contents.
- Press Command-A again to select the empty image, and press Command-C to copy it.
Step 2: Create a fake application with the empty image as an icon
- Make a new folder in the Finder (Shift-Command-N), name it and add ".app" as the suffix.
- Confirm you wish to change the name.
- Get information on the new folder (now displayed as an application), click the icon at the top of the info window, and press Command-V to paste the empty image you copied to the clipboard from Preview.
At this point, the app should apparently disappear from the Finder, but will still be selectable. You can then drag it to the Dock to create a blank space. Note that the Dock will only represent one instance of the fake program, so to create multiple spaces simply duplicate the program and add them to the Dock.