Exposé in Snow Leopard has gained a lot of new features. We've already discussed using Dock Exposé to switch between app windows in different Spaces, selecting Exposé windows by name, and using Quick Look and the Command-Tab switcher in Exposé mode. Here are two more Snow Leopard features to add to your memory banks.
The first is not really a hidden feature--Apple actually demonstrates it in the Exposé Basics video on the Exposé feature page. It isn't, however, documented anywhere in Exposé itself, nor in the Mac's help file that I can find.
Open Exposé in its All Windows mode (F3 or F9 by default), and then press Command-1. This will sort all open windows alphabetically by window title. There's no "unsort," though, so to return to the default sort order, you need to close and reopen Exposé.
There's another sort option available, too--Command-2. In the video, the narrator states that Command-2 "sorts [the open windows] by application name." But after numerous experiments by myself and other Mac OS X Hints readers, that's clearly not an accurate description.
What Command-2 seems to do is first group windows by application (so that all windows from Safari, for instance, are close to one another), and then sort all of the open windows by some algorithm--but that algorithm is not based on the application name. It may be based on application launch time, but that's just a theory. Because of this odd sorting, I find that Command-2 isn't really all that useful.
The second Exposé trick involves Exposé's Application Windows mode (Control-F3 or F10 by default). In Snow Leopard, when you use Exposé's Application Windows mode, Exposé will show you all windows from the selected application, regardless of which Space they may reside in. So if you've got Safari windows in three different Spaces, Exposé will present them all on one screen. If you then choose a window in something other than the current Space, Exposé will take you to that Space.
While this is logical, it's also a change from 10.5--in 10.5, Exposé's Application Windows mode would only show windows within the current space. If you'd prefer this behavior in Snow Leopard, too, open Terminal (in Applications -> Utilities), and enter this command:
defaults write com.apple.dock wvous-show-windows-in-other-spaces -bool FALSE
Press Return to execute the command, which won't show any output. To make this change take effect, you need to restart the Dock. You can do this using Activity Monitor (find Dock in the process list, select it, then click Quit Process), or in Terminal (type killall Dock). After the Dock restarts (which it will do automatically), activate Application Windows mode in Exposé, and you'll only see windows that reside in the current space.
If you decide you prefer the default Snow Leopard behavior, open Terminal again and enter this command (again, pressing Return to execute it):
defaults delete com.apple.dock wvous-show-windows-in-other-spaces
Restart the Dock again, and Exposé will once again show all windows in all Spaces in Application Windows mode. Thanks to Mac OS X Hints readers HitcoPhila and Mathew White for these two little Exposé tidbits.