Web Forms :: Menu Staticselected Style Is Not Working?

I am using asp menu control and binding the menu items dynamically based on the screens table from the DB. here is the code how i am binding the menu from the DB.

for (int i = 0; i < dtLeftModules.Rows.Count; i++)
{
MenuItem objLeftMenuItem = new MenuItem();
objLeftMenuItem.Text = dtLeftModules.Rows[i]["Menu_Name"].ToString();

[Code]....

but when i select the menu item the page is navigated well.. but selsctedstyle is not applying.. still showing same color.

i guess the problem with ajax postback. because i have placed the menucontrol inside the updatepanel and gave the postback trigger target control id as topmenu control id. yes leftmenu is bind based on the topmenuitem click.