<!DOCTYPE html>
<style>
/* Prevent auto viewport overflow, because that would trigger another
layout pass, hiding the bug. */
body { overflow:hidden; }
</style>
<p>There should be a green square below. No red, orange or yellow.</p>
<!-- The outer container is there to clip painting of the scrollbar,
to make it easier to write a reftest. -->
<div style="overflow:hidden; width:50px; height:50px; background:orange;">
<!-- The overflow:auto block needs auto width to be able to
reproduce the bug. Use a wide wrapper, so that the scrollbar
gets clipped. -->
<div style="width:100px; background:red;">
<div style="overflow:auto; height:50px; background:yellow;">
<div style="height:51px; background:green;"></div>
</div>
</div>
</div>