Apple’s current keyboards—laptop and desktop—can use the function keys (F1 through F12) for alternate functions such as controlling volume, screen brightness, media playback, and (on compatible laptops) keyboard backlighting, as well as for toggling Dashboard and Exposé. You choose, using the Keyboard screen of the Keyboard pane of System Preferences, whether you want these special functions to take precedence over the function keys’ standard behaviors (with standard F-key functionality requiring you to press the fn key); or if standard F-key behavior should be the default (with Apple-specific actions requiring the fn key).
This approach generally works well, but what if there are times you need to use the non-default behavior for more than a single keypress—for example, if you’re playing a Steam game, or if you’re using a graphics or video-production application, that requires standard F-keys? It’s a hassle to have to visit the Keyboard preference pane each time you need to switch.
Back in 2008, I covered FunctionFlip, a useful System Preferences pane that lets you choose the default behavior for each F-key, mixing and matching Apple and standard F-key actions. But another option—and one that’s likely more useful for the above scenarios—is Palua ($1; Mac App Store link). This simple utility adds a systemwide menu for toggling between standard F-key functionality (“Function Mode”) and the special Apple functionality (“Apple Mode”).
Just click Palua’s menu-bar icon and choose Switch To Apple Mode or Switch To Function Mode, whichever is appropriate, and all your keyboard’s F-keys switch to the desired behavior until you use Palua to switch back. Alternatively, you can use Palua’s keyboard shortcut, Option+Command+Tab, to toggle between the two modes. Unfortunately, you can’t customize this keyboard shortcut.
A nice touch is that Palua’s menu-bar icon changes to reflect the current mode: an Fn icon for Function Mode or a screen-brightness-key icon for Apple Mode.
Note that Palua is designed to work with Apple keyboards and third-party keyboards that provide similar functionality without additional software. The utility doesn’t affect the behavior of third-party keyboards, such as Logitech’s diNovo Mac Edition line, that use their own software to assign functions to F-keys.
I also encountered one bit of odd behavior: On my 11-inch MacBook Air’s built-in keyboard, Palua’s modes were backwards—in Function Mode, the F-keys performed the special Apple functions, while in Apple Mode, they acted as standard F-keys. However, this may be a MacBook Air quirk, as an Apple Keyboard connected to the same MacBook Air functioned as expected, and Palua also worked properly on other Mac laptops I tested.