Marker/Doritos not visible on 21:9 monitor on the outer sides

I play on Dell UltraSharp U2913WM 29-Inch monitor with a resolution of 2560 x 1080 and in multiplayer, all players and objects on the outer sides (I think those outside of the 16:9 middle part of the screen) have no descriptions on them. Marker/Dorito is the only term I know. 

This is really bad because you always think there is an enemy, you turn and the blue marker appears.