Menu event handler not firing

Can anyone tell me why my menu event handler doesn't work? The code is below:

protected void Menu1_MenuItemClick(object sender, MenuEventArgs e)
{
Menu1.SelectedItem.ImageUrl = "~/logo_ccMC.gif";
Label1.Text = "Clicked";
}

<asp:Menu ID="Menu1" runat="server" onmenuitemclick="Menu1_MenuItemClick" >

 

OK, if Menu Item text or value are empty than the event doesn't fire.