title: How to disable iframe from being highlighted
body: <p>When I double click the white background, the iframe becomes highlighted, how do I disable that via css?</p>
  <p><a href="https://jsfiddle.net/516y29ka/" rel="noreferrer">https://jsfiddle.net/516y29ka/</a></p>
  <p>To reproduce, double mouse click the white background and you will see the iframe become highlighted.</p>
  <p>How is that disabled via css?</p>
  <pre><code>&lt;iframe width=&quot;642&quot; height=&quot;361&quot; src=&quot;https://www.youtube.com/embed/M7lc1UVf-VE&quot; title=&quot;YouTube video player&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen&gt;&lt;/iframe&gt;
  </code></pre>
  <p><a href="https://i.stack.imgur.com/D1hB1.png" rel="noreferrer"><img src="https://i.stack.imgur.com/D1hB1.png" alt="enter image description here" /></a></p>