<!DOCTYPE html>
<style>
  #mc > div {
    position: absolute;
    inline-size: 50px;
    border: 10px solid;
  }
</style>
<p>Box shadows should not be painted at column breaks.</p>
<div id="mc" style="position:relative; margin:50px; inline-size:400px; block-size:100px; background:yellow; writing-mode:vertical-rl;">
  <div style="inset-inline-start:-10px; inset-block-start:-10px; block-size:100px; border-block-end:none;"></div>
  <div style="inset-inline-start: 140px; block-size:100px; border-block-start:none; border-block-end:none;"></div>
  <div style="inset-inline-start: 290px; block-size:50px; border-block-start:none;"></div>
</div>
