Just reporting an issue in windows 10 3x eyefinity portrait
3x 37" 1080p hdmi, dvi, hdmi(through diplayport).
windows 10 pro 64 RTM
When i setup eyefinity the mouse movement is y,x instead of x,y and is shifted:
The mouse pointer visible on the screen represents moves as if still in landscape mode (while screens are already set to portrait)
The location of the mouse pointer is not the real location of the mouse;
the true mouse coordinates (visible through clicking) are in portrait, but not matching the visible representation of the mouse cursor.
this does not happen when eyefinity is off (and 3x portrait is enabled)