I figured it out, i looked at the source code of the SDL_video.c, and there is the hint u have to set on TRUE. I broswed like hundreds of pages and it was never been mentioned. Crazy. Ok, whoever read this, just do SDL_SetHint(SDL_HINT_VIDEO_FOREIGN_WINDOW_OPENGL, "1") before initilizing SDL. After that GLContext should be set correctly. I suppose this hint came with latest updates of SDL.