/* save backbuffer content which gets lost when toggling fullscreen mode */
BlitBitmap(backbuffer, tmp_backbuffer, 0, 0, WIN_XSIZE, WIN_YSIZE, 0, 0);
/* save backbuffer content which gets lost when toggling fullscreen mode */
BlitBitmap(backbuffer, tmp_backbuffer, 0, 0, WIN_XSIZE, WIN_YSIZE, 0, 0);