VS 2010 Project Property Sheet !

Hi,
In VS 2010, I know that there is an option to add project property sheet, under "Property Manager" Menu.
But can someone explain why do we need to add a New Project Property Sheet?
Under the Solution Explorer, if You right click on the project, it let's you open up the Project Property Page, which is understandable.
Then why do even have an option to let's say go under Property Manager, and select our folder (e.g. Debug or Release), and then create a New Property Sheet !!!

Thanks in advance,
--Rudy