If you have a touch bar in your MBP, the volume control buttons will be greyed-out, but they will still work if you tap them. Thanks everyone Yes, the volume control also works fine via usb-c with MBP 15' 2019 and via micro displayport with MBP 13' 2015. MonitorControl works fine with these settings. If you want to achieve similar colors to your MBP's bulit-in P3 display, set your monitor to Color -> Preset Modes -> Standard and your macOS display profile to Display P3 (explanation: Apple uses Display P3 by default for their screens. You're saying that I don't need to the Display P3 macOS profile, but the default 'DELL U2720Q' doesn't support DCI-P3 in my case (the webkit logo is not visible).Д¬losing this issue, as I agree with summary above and there's probably not much that can be done regarding DCI-P3.ДЄlso, please keep in mind that DCI-P3 and Display P3 are two different color spaces. But I don't think I follow your last sentence. While I agree with your first sentence here - I can see the webkit logo, when I set the macOS profile to Display P3. You also does not need to change Display profile in macOS (Use 'DELL U2720QM' (or U2720Q)). Probably that's the reason why MonitorControl doesn't work, unfortunately.ДЇortunately, Display P3 gamut is working fine with other Preset Modes (Standard, Movie, or Custom Color etc.).

I haven't noticed the sentence about the default brightness set to 48cd/m2 in the manual. When you set the Color Space to sRGB the reds are washed out (for example compare the red used in the Chrome logo) Yes, I meant setting both - the Display P3 Display profile in macOS AND Color -> Preset Modes -> Color Space -> DCI-P3 in OSD, because I thought that's the correct combination used for the color calibration in the factory.

Adjust brightness on dell monitor