Unfortunately, I got an error when I did what you said.
Javascript Error : Uncaught TypeError: undefined is not a function
Example:
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>AutoHeight TabPanel - Ext.NET Examples</title>
</head>
<body>
<ext:ResourceManager ID="ResourceManager1" runat="server" />
<script src="Common/Scripts/slidingtabs.js" type="text/javascript"></script>
<ext:TabPanel ID="TabPanel1" runat="server" Width="450">
<Items>
<ext:Panel ID="Tab1" runat="server" Title="Short Text" AutoHeight="true" Padding="6">
<Content>
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Sed metus nibh, sodales
a, porta at, vulputate eget, dui. Pellentesque ut nisl. Maecenas tortor turpis,
interdum non, sodales non, iaculis ac, lacus.<br />
<br />
Vestibulum auctor, tortor quis iaculis malesuada, libero lectus bibendum purus,
sit amet tincidunt quam turpis vel lacus. In pellentesque nisl non sem. Suspendisse
nunc sem, pretium eget, cursus a, fringilla vel, urna.
</Content>
</ext:Panel>
<ext:Panel ID="Tab2" runat="server" Title="Long Text" AutoHeight="true" Padding="6">
<Content>
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Sed metus nibh, sodales
a, porta at, vulputate eget, dui. Pellentesque ut nisl. Maecenas tortor turpis,
interdum non, sodales non, iaculis ac, lacus. Vestibulum auctor, tortor quis iaculis
malesuada, libero lectus bibendum purus, sit amet tincidunt quam turpis vel lacus.
In pellentesque nisl non sem. Suspendisse nunc sem, pretium eget, cursus a, fringilla
vel, urna.<br />
<br />
Aliquam commodo ullamcorper erat. Nullam vel justo in neque porttitor laoreet. Aenean
lacus dui, consequat eu, adipiscing eget, nonummy non, nisi. Morbi nunc est, dignissim
non, ornare sed, luctus eu, massa. Vivamus eget quam. Vivamus tincidunt diam nec
urna. Curabitur velit.
</Content>
</ext:Panel>
</Items>
<Plugins>
<ext:GenericPlugin InstanceName="Ext.ux.SlidingTabs" />
</Plugins>
</ext:TabPanel>
</body>
</html>