title: Strange iframe added into body tags called `rufous-sandbox`
body: <p>I'm working on a local WordPress site, and for some reason there is an <code>iframe</code> added just after the opening <code>body</code> tag which makes the body to drop down about 20px.</p>
  
  <p>Google only returned 1 relevant result when searching for it, and what I read there didn't help much. It can be found <a href="http://wordpress.org/support/topic/my-meny-is-jumping-down?replies=7" rel="noreferrer">here</a>.</p>
  
  <p>The WordPress site has no plugins installed, and setting it to <code>display: none;</code> doesn't work.</p>
  
  <p>Here's a screenshot from Chrome so you can see it:</p>
  
  <p><img src="https://i.stack.imgur.com/9rpw7.png" alt="enter image description here"></p>