<p>On selection, this text-shadow stays on.</p>
<p class="example">On selection, this text-shadow is set to none.</p>

body {
  font-family: 'Source Sans Pro', Arial, sans-serif;
  line-height: 1.45;
  background: #E0DCCC;
  color: #333;
  padding: 1em;
}
p {
  font-size: 2em;
  font-weight: 900;
  margin-bottom: 1em;
  text-shadow: 1px 2px 1px #C79292;
}

p::selection {
  background: lightblue;
}


.example::selection {
  text-shadow: none;
}