title: Cannot read property 'removeAttribute' of null: Cant find source of it
body: <p>Im getting errors over and over again on each of my sites: </p>
  
  <pre><code>VM42958:5 Uncaught TypeError: Cannot read property 'removeAttribute' of null
  (anonymous function) @ VM42958:5
  (anonymous function) @ VM42958:20
  </code></pre>
  
  <p>Unfortunately i cant find the source of this error. If i open the related JavaScript lines i find the following:</p>
  
  <p><strong>VM42958</strong></p>
  
  <pre><code>(function()
  {
    var style = document.getElementById("9mr7n8lmeyjxk84i17g5ws714i") ||
                document.documentElement.shadowRoot.getElementById("9mr7n8lmeyjxk84i17g5ws714i");
    style.removeAttribute("id");
    Object.defineProperty(style, "disabled", {value: false, enumerable: true});
    Object.defineProperty(style.sheet, "disabled", {value: false, enumerable: true});
    var deleteRule = CSSStyleSheet.prototype.deleteRule;
    CSSStyleSheet.prototype.deleteRule = function(index)
    {
      if (this != style.sheet)
        deleteRule.call(this, index);
    }
    var removeRule = CSSStyleSheet.prototype.removeRule;
    CSSStyleSheet.prototype.removeRule = function(index)
    {
      if (this != style.sheet)
        removeRule.call(this, index);
    }
  })();
  </code></pre>
  
  <p>This is not my code and i have no idea where it is comming from or where it is used. As libraries im using bootstrap, jQuery and Chart.js.</p>
  
  <p>Does somebody know this part of code or is there a way to find the source of this error. i mean directly the line where it is appearing?</p>
  
  <p>The same error occurs in this jsFiddle for example: <a href="http://fiddle.jshell.net/leighking2/898kzyp7/" rel="noreferrer">jsFiddle</a></p>