<!DOCTYPE HTML>
<html><head>
<link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1140160">
<style>
fieldset { padding:0; }
span { display:block; width:10px; height:10px; background:lime; }
.contents { }
legend { border: 1px solid; }
.test2 legend { }
.test2 legend::after, .test3 legend::after { content:"legend"; }
.test2 legend.static, .test3 legend.static { display:block; }
.test2 legend.static::before, .test3 legend.static::before { content:"static "; }
.test2 legend.static::before { content:"static "; }
.after::after { content:"::after"; }
.before::before { content:"::before"; }
.nb legend.static  { border: 1px solid; }
.nb legend { border-style:none; }
</style>
</head>
<body>
<fieldset><div class="test contents"></div></fieldset>
<fieldset><div class="test contents">x</div></fieldset>
<fieldset><div class="test contents after"></div></fieldset>
<fieldset><div class="test contents before"></div></fieldset>
<fieldset><div class="test contents before after"></div></fieldset>
<fieldset><span></span></fieldset>
<fieldset><span></span></fieldset>
<fieldset><span></span></fieldset>
<fieldset class="test2"></fieldset>
<fieldset class="test2 after"></fieldset>
<fieldset class="test2"><legend class="static"></legend></fieldset>
<fieldset class="test2"><legend class="static contents"></legend></fieldset>
<fieldset class="test2"><legend class="static"></legend></fieldset>
<fieldset class="test2"></fieldset>
<fieldset class="test3"></fieldset>
<fieldset class="test2"><legend class="static"></legend></fieldset>
<fieldset class="test3"><legend class="static"></legend></fieldset>
<script>
document.body.offsetHeight;
var tests = document.querySelectorAll('.test');
for (i=0; i < tests.length; ++i) {
  test = tests[i];
  test.appendChild(document.createElement('span'));
}
var tests = document.querySelectorAll('.test2');
for (i=0; i < tests.length; ++i) {
  test = tests[i];
  let span = document.createElement('dummy-inline');
  span.innerHTML = "legend";
  test.appendChild(span);
}

var tests = document.querySelectorAll('.test3');
for (i=0; i < tests.length; ++i) {
  test = tests[i];
  test.appendChild(document.createElement('legend'));
}
</script>
</body>
</html>