I have a feature layer with around 1500 points. When the application initially loads all of the points should be displayed using a clusterer. Then the user should be able to filter the points based on various criteria to display a subset of the 1500 point. I thought that changing the WHERE clause and reloading the entire feature layer each time the user updates the filter would be very inefficient. So instead I created a custom clusterer that clusters selected graphics only. protected override Graphic OnCreateGraphic(GraphicCollection cluster, ESRI.ArcGIS.Client.Geometry.MapPoint point, int maxClusterCount) { if (cluster != null) { if (cluster.Any(g => g.Selected)) { var graphics = new GraphicCollection(cluster.Where(g => g.Selected)); return base.OnCreateGraphic(graphics, point, maxClusterCount); } else { return new Graphic(); } } return null; }In the application, selected points/graphics are visible and unselected points/graphics are hidden. So each time the user updates the filter, the application just selects or unselects the appropriate graphics in the feature layer. It works very well, except for one problem: missing maptips. If a graphic is part of a flare cluster, then it's maptip will display normally. But if the filter is updated such that all of the other graphics in a flare cluster are invisible, then the point appears but no maptip will be displayed. Any ideas how to fix this? I'm tempted to change the behavior and just reload the whole feature layer. Anyone have a better approach?Thanks for your help...