Previous version of Window Clippings had little control over how the background behind your selection is captured. Window Clippings 3 has a new tab just for this!
By default Window Clippings will clear the background behind the window and any shadow and produce an image with an alpha channel so that you can blend it to any background you desire.
Alternatively you can choose to clear the background only behind the shadow. This produces a really cool effect. You still get to see the desktop background through your translucent window but the shadow nicely blends into your presentation.
You can of course capture the entire visible background as it is displayed on screen.
Having control over the background of your screenshots is a great way to make your screenshots really stand out!