<!DOCTYPE html>
<style>
#scroller {
    position: fixed;
    left: 0;
    top: 0;
    width: 100px;
    height: 100px;
    overflow: scroll;
}

#bloat {
    height: 1000px;
}

#fixed {
    position: fixed;
    left: 200px;
    top: 200px;
    width: 100px;
    height: 100px;
    background: green;
}
</style>
<div id="scroller">
    <div id="bloat"></div>
    <div id="fixed"></div>
</div>
The test passes if a green box is visible on the screen. The purpose of this test is to verify fixed-position elements are not clipped by an ancestor fixed-position overflow clip.