This video tutorial demonstrates the affect the UpdatePanel's UpdateMode and ChildrenAsTriggers properties have on updating a panel's content.  The video starts out by discussing the UpdateMode property and shows why you may want to know about it when using multiple UpdatePanel controls on a single page.  It then discusses the ChildrenAsTriggers property and shows how you can prevent child controls from updating their parent UpdatePanel control.  Examples of nesting UpdatePanel controls to provide a master-details style view of data is also shown.