t-without-clearance-applied
  {
  clear: both;
  margin-top: 100px;
  }
  ]]></style>

 </head>

 <body>

  <p>Below, there should a vertical gap of<br />
  exactly 100px between 2 green bars.</p>

  <div id="parent-block">
   <div class="vertical-gap-separator"></div>
   <div id="element-without-clearance-applied"></div>
  </div>

  <div class="vertical-gap-separator"></div>

  <!--
  #element-without-clearance-applied's margin-top should collapse with #parent-block's margin-bottom: m