This bug also happens If I have TwinView off and Xinerama turned on, but slightly less problematic: the color correction settings for my primary monitor no longer gets applied to both monitors (it only affects the primary monitor, which is good), but since there is only one x screen, I can't change color correction settings for my secondary monitor anymore (at least, not from nvidia-settings). My secondary monitor in this situation has its color correction settings left with default values.
My point is that color correction settings should be a property of each individual monitor, not x screens.
This bug also happens If I have TwinView off and Xinerama turned on, but slightly less problematic: the color correction settings for my primary monitor no longer gets applied to both monitors (it only affects the primary monitor, which is good), but since there is only one x screen, I can't change color correction settings for my secondary monitor anymore (at least, not from nvidia-settings). My secondary monitor in this situation has its color correction settings left with default values.
My point is that color correction settings should be a property of each individual monitor, not x screens.