<!DOCTYPE html>
<html lang="en" class="reftest-wait">
<meta charset="utf-8">
<title>Adding a new display item to the bottom of an existing PaintedLayer shouldn't cause the other items in that layer to change layers</title>

<style>

.content {
  box-sizing: border-box;
  width: 200px;
  height: 200px;
  border: 1px solid black;
}

.fixed {
  position: fixed;
  top: 20px;
  left: 140px;
}

.onTopOfFixed {
  position: absolute;
  top: 120px;
  left: 260px;
}

.reftest-no-paint {
  border-color: lime;
}

#aboutToBecomeVisible {
  left: 20px;
}

body {
  margin: 0;
  padding: 20px;
  height: 3000px;
}

</style>

<div class="fixed content">
  <!--
    This layer is just there to force .onTopOfFixed into a PaintedLayer above
    the page background.
  -->
</div>

<div class="onTopOfFixed content" id="aboutToBecomeVisible" style="visibility: hidden">
  <!--
    This item starts out invisible but should end up in the same layer as the other
    .onTopOfFixed item, once it's visible.
  -->
</div>

<div class="onTopOfFixed reftest-no-paint content">
  <!--
    This item shouldn't repaint when the other .onTopOfFixed item becomes visible.
  -->
</div>

<script>

function doTest() {
  document.querySelector("#aboutToBecomeVisible").style.visibility = "visible";
  document.documentElement.removeAttribute("class");
}
document.addEventListener("MozReftestInvalidate", doTest, false);

</script>