Morse, Tom via colorsync-users wrote:
The monitor is calibrated using the internal monitor sensor and the correct profile is showing in display settings.
The monitor is mirroring the laptop.
I may be completely off base, but if a mirrored display is sharing the same frame buffer, then full color management can only be applied for one display target at a time. If they have different outputs then they can possibly have different calibration curves, but without detailed knowledge of the hardware and software or some judicious experimentation, that isn't certain either. So a simple explanation would be that the external display changes because the CM is switching between targeting the built in display and the external display when the internal one is switched off. Cheers, Graeme Gill.