Capture screenshot of one screen with Shift-Cmd-3?
To capture one window

⌘ Command +⇧ Shift+4+Space and click on the window you would like to capture. The window to be captured will be highlighted.



Other screenshot shortcuts

⌘ Command +⇧ Shift+3: Screenshot entire screen
⌘ Command +⇧ Shift+4: Screenshot a selected area. Click and drag to select an area to screenshot.
⌘ Command +⇧ Shift+4+Space: Screenshot one window or menu.



To save a screenshot to your clipboard and not Desktop, use Control in addition to the shortcuts defined above. When a screenshot is saved to your clipboard, you can paste the screenshot into a document, spreadsheet etc etc.



Apple provides an article on taking screenshots here: How to take a screenshot on your Mac