I have a MacBook Pro 2017, running High Sierra 10.13.3 (17D102) connected to a ThinkPad USB-C Dock, and two Dell U2412M screens attached to the dock, one by HDMI to Thunderbolt and the other by DisplayPort to DisplayPort.
OSX successfully detects both screens, as seen in Displays dialog,
But for some reasons, most of the time, the secondary screen stays turned off. It might, or might not, wake up anytime during my work on the computer. The behavior of it is pretty inconsistent.
I tried changing the connections to every possible variation, DisplayPorts only, switching ports, literally everything, but the behavior of the second screen keeps being unstable.
What am I missing? Why is the second screen mistreats me like that?