diff --git a/Unity/SiteServer.cs b/Unity/SiteServer.cs
index 4dde64b..3a686fe 100644
--- a/Unity/SiteServer.cs
+++ b/Unity/SiteServer.cs
@@ -24,7 +24,7 @@ namespace RoboidControl.Unity {
 
         public void HandleNewThing(RoboidControl.Thing thing) {
             //Debug.Log($"Handle New thing event for {thing}");
-            site.Add(thing, false);
+            //site.Add(thing, false);
             thingQueue.Enqueue(thing);
         }
 
diff --git a/src/Participant.cs b/src/Participant.cs
index 460925d..4fc8489 100644
--- a/src/Participant.cs
+++ b/src/Participant.cs
@@ -108,13 +108,13 @@ namespace RoboidControl {
         public void Add(Thing thing, bool checkId = true, bool invokeEvent = true) {
             if (checkId && thing.id == 0) {
                 thing.id = (byte)(this.things.Count + 1);
-                things.Add(thing);
+                this.things.Add(thing);
             }
             // Console.WriteLine($"added thing [{thing.networkId}/{thing.id}]"); 
             Thing foundThing = Get(thing.networkId, thing.id);
 
             if (foundThing == null) {
-                things.Add(thing);
+                this.things.Add(thing);
 
                 // if (invokeEvent)
                 //     Thing.InvokeNewThing(thing);
diff --git a/src/Participants/ParticipantUDP.cs b/src/Participants/ParticipantUDP.cs
index b2d763a..5df9e19 100644
--- a/src/Participants/ParticipantUDP.cs
+++ b/src/Participants/ParticipantUDP.cs
@@ -33,6 +33,7 @@ namespace RoboidControl {
         public ParticipantUDP(int port = 0) : base("127.0.0.1", port) {
             if (this.port == 0)
                 this.isIsolated = true;
+            Participant.AddParticipant(this);
         }
 
         /// <summary>
@@ -45,6 +46,7 @@ namespace RoboidControl {
                 this.isIsolated = true;
             else
                 this.remoteSite = new Participant(ipAddress, port);
+            Participant.AddParticipant(this);
 
             this.endPoint = new IPEndPoint(IPAddress.Any, localPort);
             this.udpClient = new UdpClient(localPort);
@@ -159,7 +161,9 @@ namespace RoboidControl {
                 if (this.isIsolated)
                     continue;
 
-                foreach (Thing thing in participant.things) {
+                //foreach (Thing thing in participant.things) {
+                for (int thingIx = 0; thingIx < participant.things.Count; thingIx++) {
+                    Thing thing = participant.things[thingIx];
                     if (thing == null)
                         continue;
 
@@ -301,10 +305,6 @@ namespace RoboidControl {
             }
         }
 
-        #endregion
-
-        #region Process
-
         protected virtual void Process(Participant sender, ParticipantMsg msg) {
 #if DEBUG
             Console.WriteLine($"{this.name} Process participantMsg {msg.networkId}");
@@ -377,9 +377,9 @@ namespace RoboidControl {
         }
 
         protected virtual void Process(Participant sender, BinaryMsg msg) {
-            // #if DEBUG            
-            //             Console.WriteLine($"Participant: Process BinaryMsg [{msg.networkId}/{msg.thingId}] {msg.dataLength}");
-            // #endif            
+#if DEBUG
+            Console.WriteLine($"Participant: Process BinaryMsg [{msg.networkId}/{msg.thingId}] {msg.dataLength}");
+#endif
             Thing thing = sender.Get(msg.networkId, msg.thingId);
             thing?.ProcessBinary(msg.data);
         }
diff --git a/src/Participants/SiteServer.cs b/src/Participants/SiteServer.cs
index d86b21c..9e36f7c 100644
--- a/src/Participants/SiteServer.cs
+++ b/src/Participants/SiteServer.cs
@@ -15,6 +15,7 @@ namespace RoboidControl {
         /// <param name="port"></param>
         public SiteServer(int port = 7681) : base(port) {
             this.name = "Site Server";
+            Participant.AddParticipant(this);
 
             Console.Write($"Prepare receive on port {port}");
             this.endPoint = new IPEndPoint(IPAddress.Any, port);
@@ -33,7 +34,11 @@ namespace RoboidControl {
         #region Update
 
         protected override void UpdateMyThings(ulong currentTimeMS) {
-            foreach (Thing thing in this.things) {
+            // We don't use foreach to prevent the 'Collection was modified' error
+            int n = this.things.Count;
+            for (int ix = 0; ix < n; ix++) {
+                Thing thing = this.things[ix];
+
                 if (thing == null)
                     continue;
 
@@ -75,7 +80,7 @@ namespace RoboidControl {
                 thing = new Thing(sender, msg.networkId, msg.thingId, msg.thingType);            
 
             if (msg.parentId != 0) {
-                thing.parent = Get(msg.networkId, msg.parentId);
+                thing.parent = sender.Get(msg.networkId, msg.parentId);
                 if (thing.parent == null)
                     Console.WriteLine($"Could not find parent [{msg.networkId}/{msg.parentId}]");
             }
diff --git a/src/Thing.cs b/src/Thing.cs
index a00774a..7e4ae16 100644
--- a/src/Thing.cs
+++ b/src/Thing.cs
@@ -90,6 +90,7 @@ namespace RoboidControl {
             this.id = thingId;
             this.type = thingType;
             this.networkId = networkId;
+            Console.Write($"New thing added to {owner}");
             this.owner.Add(this);
             InvokeNewThing(this);
         }