forcing game onto one monitor only

[manuleka]

Platform:
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Mint 13 KDE
Intel G620
GTX 460 1GB
Dell 1280x1024 (x2) Monitors
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So i've installed these linux games (all Linux native)

1. Trine 2
2. Savage 2
3. Xonotic previous (not the 2012 version)
4. Anomaly - Warzone Earth

Only Trine 2 is naturally (default) capable of running on one monitor the other 3 requires me to disable monitor 2 for it not to expand to 2560x1024 resolution

does anyone know how to set games to run on one monitor only -- may be in nVidia Settings ??? there's no setting on these games to force resolution to 1280x1024 only