Screen('Screens') on Linux

Hi

I have two displays and I want to open a window (i.e., Screen('wptr'...) just in one display. However, when I type....

Screen('Screens'), I get this output:

PTB-INFO: Display ':0' : X-Screen 0 : Output 0 [DVI-I-1]: Unknown output priority : Connected : CRTC 0 [XID 95]
PTB-INFO: Display ':0' : X-Screen 0 : Output 1 [DVI-I-2]: Unknown output priority : Connected : CRTC 1 [XID 96]
PTB-INFO: Display ':0' : X-Screen 0 : Assigning primary output as 0 with RandR-CRTC 0 and GPU-CRTC 0.

In other words, PTB just sees one screen and decides to open the window across both screens (I was testing EyelinkExample.m).

My video card is the following (using lspci):
VGA compatible controller: nVidia Corporation G96 [GeForce 9500 GT]

and displays:

1) a Dell 22" (set to 1680x1050)
2) a ViewSonic 19" (set to 1280x1024)

Both displays are connected through their DVI ports.

EyelinkSample.m frozes and doesn't allow me to kill the Screen window thus I need to go and reset the machine--the hardcore way.

Ideas?

Thanks,
Alex