Slow Scrolling on Ace Text Editor For Mobile Touch Screen Devices

As far as I’m aware, codemirror hasn’t had any performance issues for ages, so try to use that. Here’s your jsfiddle but with codemirror instead: https://jsfiddle.net/DerpMarine/j54gfecL/16/

<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.39.2/codemirror.js"></script><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.39.2/codemirror.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.39.2/mode/css/css.js"></script>
</body>
<script>

var myCodeMirror = CodeMirror(function(elt) {
  document.getElementById('editor').parentNode.replaceChild(elt, document.getElementById('editor'));
},{
  mode:  "css",
  theme: "custom", // https://codemirror.net/doc/manual.html#option_theme and https://codemirror.net/theme/
  value: document.getElementById('editor').value
});
</script>

https://codemirror.net/doc/manual.html