<!DOCTYPE html>

<html>
<head>
  <style>
    .container {
        height: 200px;
        width: 200px;
        margin: 20px;
        border: 5px solid blue;
    }
    .box {
        height: 100px;
        width: 100px;
    }
    .fixed {
        position: fixed;
        background-color: green;
        left: 50px;
        top: 50px;
    }
  </style>
</head>
<body>
    <div class="container" style="transform: translateX(0)">
        <div class="fixed box"></div>
    </div>

    <div class="container" style="will-change: transform">
        <div class="fixed box"></div>
    </div>
</body>
</html>