<div id="container">
  <div id="fixed">This is fixed</div>
</div>

<button id="foo">Add "transform:translateZ(0)" to container</button>
#container {
  background: lightgray;
  width: 200px;
  height: 200px;
  /* transform: translateZ(0); */
}
#fixed {
  background: darkgray;
  position: fixed;
  bottom: 0;
  right: 0;
}

button {
  margin-top: 30px;
}
document.getElementById('foo').onclick = function(){    
	document.getElementById('container').style.transform = 'translateZ(0)';
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.