Mini Display Port to VGA - 2nd monitor shows clean picture but displays "input not support" window

Hi guys,

I am attempting to connect an AOC monitor (Model 917Vw, manufactured in 2008) to my Macbook Pro using a Mini Displayport to VGA adapter. The connection works fine and I am getting a clean picture when I set the AOC monitor's resolution to the highest option (1600 x 1200, 60 Hz); however, the "input not support" window won't disappear and continues to traverse the entire screen, despite the clean display I am getting.

I can make this disappear by reducing the resolution, but I would prefer not to compromise resolution when I can clearly see that the monitor supports the resolution that is currently set.

Any suggestions?

Thanks,

David