I mapped the shutter --active command to alt-printscreen for taking screenshots of my active window. Unfortunately, if Shutter is already open in another workspace instead of minimized, then Shutter will not take the screenshot until after it has started moving me to the workspace that the shutter window is open in.
Paul Ferrill introduces us to the Shutter screen grab for Linux application. Shutter offers a simple interface and a whole lot of functionality. including cursor capture, whole Web page capture, and annotations.