I'm sure you figured out the issue with that. The power jack is right next to the USB. And the back of the Arduino has no power input.
But I only want to expose the USB to the outside, to reprogram the arduino, and that is it. The product should be self powered, or have a single cord to connect to the wall socket. An easy hack is to add a connector for +Vin and GND at the back:
Simply solder wires as such:
And a little hot glue to finish the job (on top and under):
I can now connect power from the back. It also clears a shield.