-1

Let me tell you how it works in Windows 7:
you point a mouse to taskbar and see a preview of some window. If you click on a mouse wheel you will close this window. There is a cross icon in a coner on a preview - this is a good idea too.
By the way: showing the window on witch preview you point the mouse cursor - is the good practise too. And yes, like it's in Windows 7.