How do I prevent the closing of modal popup window(ModalPopupExtender) on postback?

Question

I\'m using Microsoft AjaxControlToolkit for modal popup window.

And on a modal popup window, when a postback occurred, the window was closing. How do I prevent from

Answer 1

protected void Page_Load(object sender, EventArgs e)
{
    if (Page.IsPostBack)
    {
        // reshow
        MyModalPopup.Show()
    }
}