What settings did you use to get that resolution to work with this app? Do you have ATI or NVidia cards?
I ask because this doesn't seem to support anything except the ones that WoW already supports, and judging by the description in the readme, it just mimics WoW's built-in fullscreen windowed mode. I have a feeling this was created back when fullscreen windowed didn't exist?
The best I've been able to get follow this guide:
Code:
http://us.battle.net/wow/en/forum/topic/2089110733?page=1#7
The problem with the above method is it just scales the resolution down to the height and width of combined monitors to one that will fit in the main display, then scales it up. This has the consequence of low resolution video and a few other quirks, not a "true" span.