Baseline (Widescreen) Solution & Issues
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Eyefinity / Surround Specific Solution & Issues
Surround is Vert-/Hor+ . It appears to be Hor+ based upon what your single screen Aspect Ratio is. However, the character selection screen is still fully Vert-, however this doesn't effect gameplay, you can still easily identify and choose your character. This is the only menu in the game that I've seen to be Vert-. As far as character creation/customization, as well as clothing customization, and vehicle customization goes - it is all properly Hor+; however cars are split between the right bezel for me at 5040x1050, as well as the character when zoomed in very far, this can be fairly annoying at times, but it isn't game breaking in my opinion.
4k UHD Specific Solution & Issues