Web Forms :: Open Link In New Tab Is Opening Blank Page

I have designed menu using <ul> and <li> tags and handled onserverclick event, where redirection code is written. This code works fine for normal click. But when I right click on the link and select "Open link in new tab", it opens blank page. So how can I handle this scenario.

 Following is the sample code,

<ul class="rounded-corners "> <li name="menuSample"><a onserverclick="lnk_clicked" runat="server" href="~/Sample.aspx" title="Sample">Sample</a></li>
</ul>
 
Server side code:

protected void lnk_clicked(object sender, EventArgs e)
{
strPage = (sender as System.Web.UI.HtmlControls.HtmlAnchor).Title.ToString();
Response.Redirect((sender as System.Web.UI.HtmlControls.HtmlAnchor).HRef);
}