To take a picture of a menu:

Choose File > Grab > Timed Screen.

Press the mouse button to open the menu you want to capture. Keep the mouse button pressed until the “Time to screen capture has started” alert closes.
You can take a picture of a pull-down or pop-up menu so you can save or print it.
Choose File > Grab > Timed Screen.
Press the mouse button to open the menu you want to capture. Keep the mouse button pressed until the “Time to screen capture has started” alert closes.
The image is opened in Preview and saved saved to your desktop.