You are presented with a combination of keys that will allow you to take a snapshot of the active window:
For Windows: Alt + Print Screen;
For Mac: Cmd + Shift + 3 (the screenshot is placed in the file), Ctrl + Shift + Ctrl + 3 (the screenshot gets to the clipboard), Ctrl + Shift + 4 (only the desired piece of the screen gets into the file), Ctrl + Shift + Ctrl + 4 (the desired piece gets to the clipboard).
