Varför inte köra med stängt lock på MacBooken och bara ha bild på den externa?
Så gör jag och det funkar klockrent, helt utan att det hackar.
Kräver dock att man har mus eller tangentbord anslutet.
Från manualen:
Using Your MacBook with the Display Closed
You can use your MacBook with the display closed if the computer is connected to an
external monitor, keyboard, and mouse.
Important: To use your MacBook with the display closed, the MacBook must be
plugged into a functioning power outlet.
To operate your computer with an external monitor attached and the display closed:
1. Connect a USB keyboard and mouse to your MacBook.
2. Connect the power adapter to the MacBook and a power outlet. Check that the power
adapter light is on.
3. Close the MacBook display to put the computer to sleep.
4. Follow the steps in the previous section to connect your MacBook to an external
display.
5. Wait a few seconds and then press any key on the external keyboard to wake the
MacBook.