title: Setting overflow-x: hidden adds a vertical scrollbar
body: <p>When I specify <code>overflow-x: hidden</code> on an element which overflows both horizontally and vertically, the element gets a vertical scroll bar in addition to hiding the horizontally overflowing content. I have tried adding <code>overflow-y: visible</code> and even just <code>overflow: visible</code>, to no effect.</p>
  
  <p>Am I misunderstanding what these properties do? I would think that <code>overflow-x</code> should not affect the vertical overflow at all.</p>
  
  <p>This has happened on every browser I've tried.</p>
  
  <p>Here's a snippet which demonstrates the effect. I'm using <code>&lt;pre&gt;</code> tags because they're an easy way to create overflowing content, but it seems to happen with any tag.</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>pre {
    height: 40px;
    width: 150px;
    margin-bottom: 50px; /* We need this so they don't overlap. */
  }
  
  #x-hidden {
    overflow-x: hidden;
  }
  
  #y-visible {
    overflow-x: hidden;
    overflow-y: visible;
  }
  
  #visible {
    overflow: visible;
    overflow-x: hidden;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;pre&gt;
    Lorem ipsum dolor sit amet, consectetur adipiscing elit.
    Praesent bibendum lorem felis, sit amet sodales nunc gravida eget.
    Integer mollis quis magna quis vulputate.
    Cras aliquet convallis efficitur.
  &lt;/pre&gt;
  
  &lt;pre id="x-hidden"&gt;
    Lorem ipsum dolor sit amet, consectetur adipiscing elit.
    Praesent bibendum lorem felis, sit amet sodales nunc gravida eget.
    Integer mollis quis magna quis vulputate.
    Cras aliquet convallis efficitur.
  &lt;/pre&gt;
  
  &lt;pre id="y-visible"&gt;
    Lorem ipsum dolor sit amet, consectetur adipiscing elit.
    Praesent bibendum lorem felis, sit amet sodales nunc gravida eget.
    Integer mollis quis magna quis vulputate.
    Cras aliquet convallis efficitur.
  &lt;/pre&gt;
  
  &lt;pre id="visible"&gt;
    Lorem ipsum dolor sit amet, consectetur adipiscing elit.
    Praesent bibendum lorem felis, sit amet sodales nunc gravida eget.
    Integer mollis quis magna quis vulputate.
    Cras aliquet convallis efficitur.
  &lt;/pre&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>The <a href="https://www.w3.org/TR/css3-box/#overflow-x" rel="noreferrer">W3C spec</a> says:</p>
  
  <blockquote>
    <p>The computed values of ‘overflow-x’ and ‘overflow-y’ are the same as their specified values, except that some combinations with ‘visible’ are not possible: if one is specified as ‘visible’ and the other is ‘scroll’ or ‘auto’, then ‘visible’ is set to ‘auto’.</p>
  </blockquote>
  
  <p>But this makes no mention of the case when <code>overflow-x</code> or <code>overflow-y</code> is set to <code>hidden</code>, which to me implies that this combination is indeed meant to be possible.</p>