What could possibly be “unexpected” when it comes to those four humble directional keys? Perhaps it’s that, totally unadorned (that is, without a modifier such as Command or Control), they can do more than just move an insertion point around in text or select something in a list.
1. Select Finder items in icon view
When you’re in a Finder window looking at files using the icon view (View -> As Icons), pressing Tab selects the next alphabetic item no matter where its icon may be. But what if you want the item next to the currently selected one (or above or below it)? You don’t need your mouse or trackpad for this basic task. Use an arrow key to move to the item—even if it’s in a different row because the window’s sorted into groups with the Arrange By command.
2. Expand folders in the Finder
If you want to display a selected folder’s contents when you’re in a Finder list view window (View -> As List), don’t bother clicking on the expansion arrow. Instead, just press the Right arrow to expand a selected folder; press Left arrow to collapse it. (Adding Option when you expand a folder expands all its subfolders, too.)
This folder-expansion trick works in lists in Open and Save dialog boxes, too.
3. Scroll windows in Preview or Safari
In Apple’s Preview or Safari, you can the scrollbar to move up and down through the window. Or keep your hands on the keyboard and press the Up or Down arrow key to scroll a little bit at a time. Usually you’ll move the equivalent of one or two lines of text, although your mileage will vary based on the zoom level you’re using.
Bonus Tip To scroll down in bigger chunks, press the spacebar; press Shift-spacebar to scroll up.
4. Move in and between menus
If you’ve clicked to open a menu, perhaps you’ve noticed that the arrow keys let you move through its commands. But you can also open the menu itself, and move to others, using the arrow keys.
The key to this trick is turning on the initial controls in the Keyboard Shortcuts pane of Keyboard preferences. Click Keyboard & Text Input on the left, and in the list at the right, check the boxes for Move Focus To The Menu Bar and Move Focus To The Status Menus.
Trigger these commands using their default shortcuts (Control-F2 for the Menu bar and Control-F8 for the Status Menu—those little icons on the right side of the menu bar). When you do, the first menu, or first status menu icon, is highlighted. Use the Left or Right arrow key to move to the menu you want. Press Down arrow to open a selected menu and then use the Up and Down arrows to move through the command. Press Return or the spacebar to trigger a command or, if you reach a submenu’s title, press Right arrow to pop it open.
(If you’re wondering why the arrow keys don’t seem to work with many items in the status menu, you’re not alone. My testing revealed this trick to generally apply only to items supplied by the OS. On my Mac, Dropbox, Twitterific, and QuicKeys icons are ignored in the selection cycle.)
5. Play a different tune in iTunes
When you’re listening to your music in iTunes, the Up and Down arrows select the previous or next item in your playlist, but don’t affect what’s playing. Use the Left or Right arrow to play the previous or next track—relative to what’s currently playing, not to what’s selected. (There’s no need to press Command along with the arrow keys, despite what’s noted in the Controls menu.)
6. Control Safari’s autofill
When you start to fill out a website form—a single letter in one field is often enough—Safari will show a pop-up with one or more suggestions as to where it might grab the information for the form. Save yourself the effort of a click or tap: Press the Down arrow when you see the pop-up to select what information you want used, and then press Return.