Yes, it will be disconnected from the PC - when it is disconnected, the LEDs will only be on/off (depending on the power switch). When it is connected the LEDs will be controlled by Unreal Engine (Nano pins), but I would like them to depend on the power switch as well - if the power switch is off, the LEDs are off and cannot be controlled by Unreal Engine.
The power switch is on the 5V line from the adaptor.