title: Why do fixed elements slow down scrolling in Firefox?
body: <p>Why do elements with the CSS <code>position: fixed</code> applied to them cause Firefox to eat 100% CPU when scrolling the page they are in? And are there any workarounds?</p>
  
  <p>I've noticed this behavior on a few sites, for example the notification bar at the top of the page on StackOverflow. I'm using Linux in case that matters.</p>