chromium/third_party/blink/web_tests/fast/multicol/under-scroll.html

<!doctype HTML>
<style>
#target::-webkit-scrollbar {
    display: none;
}
</style>
<div id=target style="overflow: scroll; width: 300px; height: 200px;">
  <div style="columns: 2; width: 200px; height: 100px">
    <div style="width: 100px; height: 100px; background: lightblue"></div>
    <div style="width: 100px; height: 100px;  background: lightgray"></div>
  </div>
  <div style="width: 100px; height: 300px"></div>
</div>
<script>
target.scrollTop = 50;
</script>