Hello,  I have 2 Mac computers with 2 and 3 monitors, respectively.  One of them has 2 identical monitors and when you ask to see screen for monitor 1 or monitor 2 (they are both shown as Dell E2210), I get the same image.  The other one as 2 identical displays (shown as Philco) and a Panasonic Display.  When I ask to seek the Panasonic screen, it displays correctly, but the images either Philco screen is identical.  Hope this helps.