<!DOCTYPE html>
<title>Layout Instability: shift with counterscroll not counted</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<style>

#s {
  overflow: scroll;
  position: absolute;
  left: 20px;
  top: 20px;
  width: 200px;
  height: 200px;
}
#sp {
  width: 170px;
  height: 600px;
}
#ch {
  position: relative;
  background: yellow;
  left: 10px;
  top: 100px;
  width: 150px;
  height: 150px;
}

</style>
<div id="s">
  <div id="sp">
    <div id="ch"></div>
  </div>
</div>
<sc