Have you updated your firmware? You must also select the game mode on your console to split screen. If you go to the video options there is a side split/ top bottom split option. Check it out or post a screen shot of your problem.
I have lG 55LW6500 and I buy additional LG 3D glass for dual play. But when I start game in xbox and spilt for two user and goto TV 3D menu and try to activate Side by side -SBS option but it is deactivate. only 2D to 3D option is available. Please can you help me how i can activate this function..