it worked!thanks for your answer 

我在下载的demo目录中的window.html中加了一个简单的datagrid组件。代码如下所示。
当我用IE7打开的时候，发现window中有滚动条时，拖动滚动条，但datagrid不跟随滚动，而其他内容滚动正常。我在IE8中测试了一下，滚动时，datagrid是工作正常的。

Code:

           <div id="w" class="easyui-window" title="My Window" iconCls="icon-save" style="width:500px;height:200px;padding:5px;">
		<div class="easyui-layout" fit="true">
			<div region="center" border="false" style="padding:10px;background:#fff;border:1px solid #ccc;">
				jQuery EasyUI framework help you build your web page easily.
				<br/><br/>
				click <a href="#" onclick="test()">here</a> to popup another window.
				<table class="easyui-datagrid" style="height: 400px;">
					<thead>
						<tr>
							<th field="name" width="80">aaaaaa</th>
							
						</tr>
					</thead>
				</table>
			</div>
			<div region="south" border="false" style="text-align:right;height:30px;line-height:30px;">
				<a class="easyui-linkbutton" iconCls="icon-ok" href="javascript:void(0)" onclick="resize()">Ok</a>
				<a class="easyui-linkbutton" iconCls="icon-cancel" href="javascript:void(0)" onclick="resize()">Cancel</a>
			</div>
		</div>
	</div>