chromium/third_party/blink/web_tests/external/wpt/html/editing/dnd/overlay/outside-viewport-001.html

<!DOCTYPe html>
<meta charset='utf-8'>
<title>drag and drop – feedback overlay of elements partly outside the viewport – 001</title>
<style>
a {
  display: block;
  height: 200px;
  width: 200px;
  background-color: blue;
  position: absolute;
  top: 10px;
  right: -100px;
}

p {
 margin-right: 200px;
}
</style>

<a href='#'></a>

<p>Drag the blue box on the right downwards. The drag placeholder should ideally be a blue square. It may optionally be a rectangle the same shape as the visible part of the blue box. No part of the UI should be dragged with the box.</p>