Horizon on a 4K / HiDPI screen performs incredibly poorly.
Upon moving the mouse, it can take up to 45 SECONDS for the on-screen mouse pointer to move to the correct position - and during that time, click events are delivered at the WRONG screen coordinates.
The behaviour described is identical to the concerns raised in this thread
I raise it here as a separate item because it appears to be directly relevant to using a 4K / HiDPI external display.
