New tab in Product Details

Hello,

I created a new tab when viewing the product details.

<ajaxToolkit:TabContainer runat="server" ID="ProductsTabs" ActiveTabIndex="1" CssClass="grey">
            <ajaxToolkit:TabPanel runat="server" ID="pnlProductInfoDetails" HeaderText="Full Description">
                <ContentTemplate>
                    <nopCommerce:ProductInfoDetails ID="ctrlProductInfoDetails" runat="server">
                    </ NopCommerce: ProductInfoDetails>
                </ ContentTemplate>
            </ AjaxToolkit: TabPanel>

It turns out that by default it keeps the focus on the 'product reviews'
And I wanted the focus to stay on the tab that I created in order to view its contents.

I tried to change
<ajaxToolkit:TabContainer runat="server" ID="ProductsTabs" ActiveTabIndex="1" CssClass="grey"> putting activeindex with another number (0 or 2), but nothing changes.

Can someone help me?