Code:
<!DOCTYPE HTML>
<html>
<head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">

    <!--Ext and ux styles -->
    <link href="../../../extjs-4.2.0.489/resources/css/ext-all.css" rel="stylesheet" type="text/css" />

	<!--Ext lib and UX components-->
    <script src="../../../extjs-4.2.0.489/ext-all-debug.js" type="text/javascript"></script>

</head>
<body>
    <ul><li>Showing disc image</li></ul>
<h3>margin-top</h3>
</body>
</html>
Launch this in latest Chrome on Mac, you'll see discs for the list and a margins for the h3-tag.

These are not reset.
Code:
-webkit-margin-before: 1em;
-webkit-margin-after: 1em;
-webkit-margin-start: 0px;
-webkit-margin-end: 0px;