Tech Tricks

Single-application mode is how the iPhone works, of course, and on the Mac, almost all Apple applications – think about Mail, iTunes, and iPhoto – rely on a single window that can easily take over the entire screen. When an application needs a second window, such as for keywords or editing in iPhoto, it is generally a palette that disappears when the application is not in the foreground.

But it goes further. Lurking in the scary bowels of Mac OS X for all these years has been this little command, which brings back single-application mode. (Go ahead and try it – it’s easily reversed.)

defaults write com.apple.dock single-app -bool true

For single-application mode to take effect, you have to relaunch the Dock with this second command.

killall Dock

Getting back to the normal multi-application mode is easy. Just paste this first command into Terminal and then restart the Dock with the second command.

defaults delete com.apple.dock single-app
killall Dock