This example shows how to configure Redactor X if it's inside a scrollable layer.
<!DOCTYPE html>
<html>
<head>
<title>Redactor X</title>
<meta charset="utf-8">
<!-- css -->
<link rel="stylesheet" href="/your-dist-path/redactorx.min.css" />
</head>
<body>
<!-- element -->
<div id="target" style="position: relative; overflow: auto; height: 450px;">
<textarea id="entry">
<p>Content</p>
</textarea>
</div>
<!-- js -->
<script src="/your-dist-path/redactorx.min.js"></script>
<!-- call -->
<script>
RedactorX('#entry', {
editor: {
scrollTarget: '#target'
}
});
</script>
</body>
</html>