I have os10 and I have followed instructions, however: THERE IS NO ARRANGEMENT TAB PRESENT.
Video mirroring
Mirroring displays the same image on each display.
- Make sure your additional display is properly connected and powered on.
- From the Apple () menu, choose System Preferences.
- From the View menu, choose Displays.
- Click the Arrangement tab.
- Enable (check) "Mirror Displays" in the bottom-left corner.
THERE IS NO ARRANGEMENT TAB ON MY DISPLAYS PAGE !!!!!
MacBook Pro, iOS 7.0.4