I just found a tip for Windows that I never knew about. You probably know that pressing the Print Screen button places a screen capture onto the clipboard so you can paste it into Word or anywhere else.
What you may not know is that holding down the ALT button while pressing Print Screen will capture only the frontmost (or current) window and place it onto the clipboard. No more advertising to the world what applications you were running and how much cruft you’ve got littering your system tray!