I´m trying to configure a 4 projectors blending system but when I open the advanced output tab I cannot see the preview monitor to adjust edge overlap, blending, etc... I can see it through the output on the projectors but not in the main screen so it´s nearly imposible to adjust it because i don´t know where the cursor is, I don´t get a black image on the preview monitor but something like a part of the screens "behind" or the windows desktop.
I´m using a matrox C680 graphic card with up to date drivers and the PC is an HP Z230 workstation