Disable Laptop display or clamshell mode
Thank you for the feedback ! SwitchResX excluded the internal monitor, in the sense that the mouse can't go on the other screen...
On my MacookPro TB3 the back-lighting is still active, the keyboard lightning is active, the Touch Bar stay active and when you open the properties of the monitor in System Preferences, it will open the two windows corresponding of the screens.
Do you have better solutions ?