Yeah, now it works, I'm going to study the new code.   There's still a particular useful case where something goes crazy: that's when you don't have any element before and after the horizontal scroll, that is remove the 2 divs .other. Now if you scroll a bit, then back to the start and scroll again you'll see the container doesn't remain fixed, I suppose. We maybe need to reset or something the timeline? You know what causes that?