when I enable the fullscreen mode in Cogs, it shows the single screen centered over both monitors instead of on the primary monitor.

using nvidia twinview

Processor Information:
    Vendor:  AuthenticAMD
    Speed: 3200 Mhz
    4 logical processors
    4 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Supported
    SSE41:  Unsupported
    SSE42:  Unsupported

Network Information:
    Network Speed:  

Operating System Version:
    "openSUSE 12.2 (x86_64)" (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.4.11-2.16-desktop
    X Server vendor:  The X.Org Foundation
    X Server release:  11203000

Video Card:
    Driver:  NVIDIA Corporation GeForce GTX 275/PCIe/SSE2

    Driver Version:  3.3.0 NVIDIA 310.19
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 59 Hz
    VendorID:  0x10de
    DeviceID:  0x5e6
    Number of Monitors:  2
    Number of Video Cards Not Detected
    Primary Display Resolution:  1680 x 1050
    Desktop Resolution: 2960 x 1050
    Primary Display Size: 17.05" x 10.67"  (20.08" diag)
                                            43.3cm x 27.1cm  (51.0cm diag)
    Primary Bus: PCI Express 16x
    Primary VRAM: 896 MB
    Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
    Audio device: Nvidia MCP77/78 HDMI

Memory:
    RAM:  8000 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_US.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  379516 Mb
    Largest Free Hard Disk Block:  107965 Mb

Installed software:

Recent Failure Reports:
    Mon Jan  7 14:02:31 2013 GMT: file ''/tmp/dumps/crash_20130107150228_1.dmp'', upload yes: ''CrashID=bp-43371201-8492-49cd-91a4-bf5552130107''