  var video = old.$("video");
      if (video) {
        video.pause();
      }
    }
    if (next) {
      next.setAttribute("aria-selected", "true");
      if (this.html.classList.contains("view")) {
        next.scrollIntoView();
      }
      var video = next.$("video");
      if (video && !!+this.params.autoplay) {
        video.play();
      }
    } else {
      // That should not happen
      this.idx = -1;
      // console.warn("Slide doesn't exist.");
    }
  }

  Dz.setIncremental = function(aStep