Using setInterval to update scroller items

I'm tinkering around with the scroller (on a Bangle 2) and I was wondering if there was a way to update scroller items using, say, setInterval. As a quick example:

var list = [];
list[0] = 10;
list[1] = 20;
list[2] = 30;
list[3] = 40;
list[4] = 50;
list[5] = 60;
list[6] = 70;

E.showScroller({
  h : 40, c : list.length,
  draw : (idx, r) => {
    setInterval(function() {
      g.clearRect(r.x,r.y,r.x+r.w-1,r.y+r.h-1);
      g.setFont("6x8:2").drawString(list[idx],r.x+10,r.y+4);
      list[idx]--;
    }, 1000);
  },
  select : (idx) => console.log("You selected ", idx)
  }
);

If all items fit on the screen, it works fine, but when you start scrolling, the menu starts glitching. Is there a good way to have the items show up properly?