Think positively, this should not be a kind of bug brought by Leopard. This should be called 'The Leopard Hidden Selection'.
This feature (or bug?) comes with our trusted new Leopard Spaces. It's brought by assigning Finder into one of Leopard Spaces. You may look at my other article Leopard Take A Look - Spaces for reference.
Finder is not located inside your usual Application folder. Finder is located at
Macintosh HD → System → Library → CoreServices. After you found it, assign it to one of your Leopard Spaces, for example Space 5.
When you got yourself at Space 5, you still have your selection. Now, let's try to go to other Spaces and draw a selection using your mouse. You will see the magic selection : The Hidden Selection.
Some articles taken from our resource base, tightly related to current article, to empower you with more knowledge on tweaking the most out of your Mac.