Hi Xiaolin
I've tested this on my server and did not see any issues with 1.2.5. The code I used to test with is below (similar to the demo software). I've also tested this with jQuery 1.7.1 without any issues.
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="keywords" content="jquery,ui,easy,easyui,web">
<meta name="description" content="easyui help you build your web page easily!">
<title>Create Dialog - jQuery EasyUI Demo</title>
<link rel="stylesheet" type="text/css" href="
http://www.jeasyui.com/easyui/themes/default/easyui.css">
<link rel="stylesheet" type="text/css" href="
http://www.jeasyui.com/easyui/themes/icon.css">
<script type="text/javascript" src="
http://code.jquery.com/jquery-1.6.1.min.js"></script>
<script type="text/javascript" src="
http://www.jeasyui.com/easyui/jquery.easyui.min.js"></script>
</head>
<body>
<h2>Create Dialog</h2>
<div id="dd" class="easyui-dialog" style="padding:5px;width:400px;height:200px;"
title="My Dialog" iconCls="icon-ok" minimizable="true" maximizable="true" collapsible="true" closable="true"
toolbar="#dlg-toolbar" buttons="#dlg-buttons">
Dialog Content.
</div>
<div id="dlg-toolbar">
<a href="#" class="easyui-linkbutton" iconCls="icon-add" plain="true" onclick="javascript:alert('Add')">Add</a>
<a href="#" class="easyui-linkbutton" iconCls="icon-save" plain="true" onclick="javascript:alert('Save')">Save</a>
</div>
<div id="dlg-buttons">
<a href="#" class="easyui-linkbutton" iconCls="icon-ok" onclick="javascript:alert('Ok')">Ok</a>
<a href="#" class="easyui-linkbutton" iconCls="icon-cancel" onclick="javascript:$('#dd').dialog('close')">Cancel</a>
</div>
</body>
</html>