Windows: Don't lose the existing current GL context in SDL_CreateWind…

…ow().

Fixes Bugzilla #1395.

src/video/windows/SDL_windowswindow.c

@@ -231,10 +231,15 @@ WIN_CreateWindow(_THIS, SDL_Window * window)
     }
 #if SDL_VIDEO_OPENGL_WGL
     if (window->flags & SDL_WINDOW_OPENGL) {
+        /* The current context is lost in SDL_GL_SetupWindow; recover it. */
+        SDL_Window *current_win = SDL_GL_GetCurrentWindow();
+        SDL_GLContext current_ctx = SDL_GL_GetCurrentContext();
         if (WIN_GL_SetupWindow(_this, window) < 0) {
             WIN_DestroyWindow(_this, window);
+            WIN_GL_MakeCurrent(_this, current_win, current_ctx);
             return -1;
         }
+        WIN_GL_MakeCurrent(_this, current_win, current_ctx);
     }
 #endif
     return 0;