Screen capture of just one window

If you want to take a screen capture of just one window, there's a little-known keyboard shortcut you should get to know.

Press Shift-Command-Spacebar-4 (in that order), then release all the keys at once. Your cursor will then change into a large camera.

Click this camera cursor on the window you you would like to capture, and it will create a PDF of just that window, which will be placed on your desktop named Picture 1.pdf