title: Why is absolute child of a sticky is always hiding behind another sticky?
body: <p>I am trying to have a sticky first column as well as some CSS tooltips. Here is a simplified model of my setup:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>div.container
  {
    width: 300px;
    overflow: auto;
  }
  
  table
  {
    border-collapse: collapse;
  }
  
  td 
  {
    border: 1px black solid;
  }
  
  
  td div 
  {
    width: 80px;
    height: 30px;
  }
  
  td:first-child
  {
    position: sticky;
    left: 0;
    background-color: lime;
  }
  
  
  [data-tooltip]:hover:after
  {
    content: attr(data-tooltip);
    position: absolute;
    background: white;
    top: 22px;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!doctype html&gt;
  &lt;div class="container"&gt;
    &lt;table&gt;
      &lt;tr&gt;
        &lt;td&gt;&lt;div data-tooltip="123"&gt;hover me&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
      &lt;tr&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
        &lt;td&gt;&lt;div&gt;&lt;/div&gt;
    &lt;/table&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>The problem is that the tooltip hides behind the cell on the next row and I can't find any solution for that (other than removing <code>position: sticky</code>) which is not an acceptable solution in my case.</p>
  
  <p>What should I do to bring the tooltip in front? <code>z-index</code> seems to do nothing in this case.</p>