When Steve Jobs first unveiled OS X 10 years ago, the Finder operated in single application mode, a funky setup whereby switching into a program would minimize all other running applications. In that respect, the first betas of OS X bore a striking resemblance to the iPhone OS of today. Apple soon did away with single application mode, but the option to turn it back on has resided in the bowels of OS X for some time, and activating it via Terminal commands has always been pretty straight forward.
But Snow Leopard makes things a whole lot easier, and enables the same functionality without ever having to open up the Terminal app.
One of the cooler dock features in Snow Leopard (and this actually also works in Leopard) is the ability to activate single application mode from the dock itself. Let’s say that you have a bunch of applications open, but you’d like to switch to Text Edit and minimize all of the other open apps so that you can start writing a thank-you letter to yours truly without any distractions. You could, of course, switch over to Text Edit and hide all the other open apps by pressing command-option-H, but if you want to quickly scan a few apps individually, that technique is bound to get tedious.
In Snow Leopard, and using the example above, you can instantly switch over to Text Edit and hide all other apps simply by clicking on the Text Edit icon in the dock while simultaneously pressing command-option. This brings all open (i.e non-minimized) Text Edit windows to the forefront and pushes all other app windows into the background. This feature is a great way to efficiently navigate through all of your open apps without having to needlessly clutter up your desktop.
Pushing things further, once you have a single app in the foreground, you can easily bring another app up by clicking on any icon in the dock or by using the application switcher (command-tab). This functionality works great when you have, for example, 8 apps open and you want to quickly make Mail and Tweetie the only 2 visible apps.
Check out the screencast below to see this little trick in action.