ThisWorkbook_GroupsCollapsedOrExpanded ( Object sender, GroupsCollapsedOrExpandedEventArgs e ) { Debug.Assert(e != null); AssertValid(); // Set the collapsed group locations only if the groups were collapsed // or expanded as a result of a user's collapse or expand command, not // as a result of the graph pane being refreshed. When the graph pane // is refreshed, the GraphLaidOut event takes care of setting the // collapsed group locations. if (e.GroupsRedrawnImmediately) { SetLocationsOfCollapsedGroups(e); } }