SurroundFix 

SurroundFix is a simple and lightweight AddOn that fixes the problems associated with running WoW at Surround/Eyefinity/Triplewide resolutions!

Features
- Constrains the UI to the middle display
- Automatic vertical resolution detection
- Automatic middle display aspect ratio detection
- Extremely lightweight and simple, every Blizzard UI element acts as if you're just using a single display
- Almost every addon also works, so long as their frame handling is done properly!
- Will do nothing if using a single display, no need to disable it!
- Ability to set a manual aspect ratio for the UI - Want 16:9 on your 21:9 monitor? No problem!

Configure various options with /sfix or /surroundfix. You can change the aspect with "/sfix aspect x:y", or set it back to automatic mode with "/sfix aspect auto". Just type the command and any arguments for more help!






For the curious, the mod essentially resizes the UIParent frame to the resolution of your middle monitor. This means that every UI element and AddOn sees a normal sized display rather than a crazy wide one, so they perfectly orient themselves on the middle display.

This is a much better solution than manually positioning every UI element, and also means that if you switch back to a single display your UI won't break! In fact, it can handle switching between Triplewide and single on the fly!