Put Back
In the latest Snow Leopard build the "Put Back" feature will restore any accidental disposals to their original location.
Stacks Folder Navigation
Clicking on a folder in Stacks will now open the folder in the Stacks window while shrinking the parent window as a small icon on the top left. Previously clicking a folder while in Stacks would open the folder in a new Finder window.
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(MacRumors Mockup)