In PresenceDetector.OnConnectionClose(), use the IsChildAgent check already available on IClientAPI.SceneAgent rather than retrieving it again by scanning all scenes.

OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs

@@ -490,12 +490,12 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// </summary>
         public void Close()
         {
+            IsActive = false;
+
             m_log.DebugFormat(
                 "[CLIENT]: Close has been called for {0} attached to scene {1}",
                 Name, m_scene.RegionInfo.RegionName);
 
-            IsActive = false;
-
             // Shutdown the image manager
             ImageManager.Close();