16.04 - Mednafen fullscreen spans multiple monitors - Ask Ubuntu

i having problem mednafen in fullscreen mode. works great windowed, when go fullscreen mode spans across both monitors, making games impossible play. know of way can go fullscreen on 1 monitor?

i'm using ubuntu 16.04lts , mednafen 0.9.38.7. video section initialization screen -

 initializing video...   video driver: opengl   video mode: 768 x 672 x 32 bpp   pixel shader: none   fullscreen: no   special scaler: none   scanlines: off   destination rectangle: x=0, y=0, w=768, h=672   opengl implementation: intel open source technology center mesa dri intel(r) ivybridge desktop  3.0 mesa 11.2.0 

any suggestions or advice appreciated.

thanks in advance

the way i've been able work edit mednafen-09x.cfg file so:

;full-screen horizontal resolution. nes.xres 1920

;full-screen vertical resolution. nes.yres 1080

by default, these values set 0. 2 monitors causes mednafen split video output across both of them dead center - making unplayable.

you'll need each system want emulate in cfg file. change default value of 0 monitor's resolution , it'll work. downside kills signal #2 monitor while game running.