<!DOCTYPE html>
<html>
<style>
    body { margin: 20; }
    .styled {
        padding: 20px;
        height: 70px;
        background-color: aqua;
        border-radius: 20px;
    }
</style>
<body>
<select>
    <option>This is an option</option>
</select>
<select style="width: 100px;">
    <option>This is an option that should overflow and clip</option>
</select>
<select class="styled">
    <option>This is a styled option</option>
</select>
<select class="styled" style="width: 100px;">
    <option>This is a styled option that should overflow and clip</option>
</select>


<pre id="results"></pre>
<script>
if (window.testRunner)
    testRunner.dumpAsText();

window.onload = function () {
    if (window.internals)
       results.textContent = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_EVENT_REGION | internals.LAYER_TREE_INCLUDES_ROOT_LAYER_PROPERTIES);
};
</script>
</body>
</html>