From c2afe0b6b2806b68cd9ff70f2af7e0c305fe72e0 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Thu, 29 Apr 2021 15:22:10 +0200
Subject: [PATCH] Fix synchronizing ActorTreeNode order after actor duplicate

#487
---
 Source/Editor/SceneGraph/ActorNode.cs         |  4 ++--
 Source/Editor/SceneGraph/GUI/ActorTreeNode.cs |  4 ++++
 Source/Editor/SceneGraph/SceneGraphNode.cs    | 13 ++-----------
 Source/Engine/Level/Actor.cpp                 |  3 +--
 Source/Engine/UI/GUI/ContainerControl.cs      |  2 ++
 5 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/Source/Editor/SceneGraph/ActorNode.cs b/Source/Editor/SceneGraph/ActorNode.cs
index 017cff3bf..3542feb03 100644
--- a/Source/Editor/SceneGraph/ActorNode.cs
+++ b/Source/Editor/SceneGraph/ActorNode.cs
@@ -194,7 +194,7 @@ namespace FlaxEditor.SceneGraph
         {
             get
             {
-                var scene = _actor.Scene;
+                var scene = _actor ? _actor.Scene : null;
                 return scene != null ? SceneGraphFactory.FindNode(scene.ID) as SceneNode : null;
             }
         }
@@ -235,7 +235,6 @@ namespace FlaxEditor.SceneGraph
             {
                 if (!(value is ActorNode))
                     throw new InvalidOperationException("ActorNode can have only ActorNode as a parent node.");
-
                 base.ParentNode = value;
             }
         }
@@ -299,6 +298,7 @@ namespace FlaxEditor.SceneGraph
             // (eg. we build new node for spawned actor and link it to the game)
             if (_treeNode.Parent != null && !_treeNode.Parent.IsLayoutLocked)
             {
+                _treeNode.IndexInParent = _actor.OrderInParent;
                 _treeNode.Parent.SortChildren();
 
                 // Update UI
diff --git a/Source/Editor/SceneGraph/GUI/ActorTreeNode.cs b/Source/Editor/SceneGraph/GUI/ActorTreeNode.cs
index 7b4b35ed1..2c050c2e3 100644
--- a/Source/Editor/SceneGraph/GUI/ActorTreeNode.cs
+++ b/Source/Editor/SceneGraph/GUI/ActorTreeNode.cs
@@ -86,6 +86,10 @@ namespace FlaxEditor.SceneGraph.GUI
                 }
                 parent.SortChildren();
             }
+            else if (Actor)
+            {
+                _orderInParent = Actor.OrderInParent;
+            }
         }
 
         internal void OnNameChanged()
diff --git a/Source/Editor/SceneGraph/SceneGraphNode.cs b/Source/Editor/SceneGraph/SceneGraphNode.cs
index 6cf83647a..bc8fe84aa 100644
--- a/Source/Editor/SceneGraph/SceneGraphNode.cs
+++ b/Source/Editor/SceneGraph/SceneGraphNode.cs
@@ -112,18 +112,9 @@ namespace FlaxEditor.SceneGraph
             {
                 if (parentNode != value)
                 {
-                    if (parentNode != null)
-                    {
-                        parentNode.ChildNodes.Remove(this);
-                    }
-
+                    parentNode?.ChildNodes.Remove(this);
                     parentNode = value;
-
-                    if (parentNode != null)
-                    {
-                        parentNode.ChildNodes.Add(this);
-                    }
-
+                    parentNode?.ChildNodes.Add(this);
                     OnParentChanged();
                 }
             }
diff --git a/Source/Engine/Level/Actor.cpp b/Source/Engine/Level/Actor.cpp
index ef5b2a554..21e2ae050 100644
--- a/Source/Engine/Level/Actor.cpp
+++ b/Source/Engine/Level/Actor.cpp
@@ -1597,7 +1597,7 @@ bool Actor::FromBytes(const Span<byte>& data, Array<Actor*>& output, ISerializeM
         // Order in parent
         int32 orderInParent;
         stream.ReadInt32(&orderInParent);
-        order.At(i) = orderInParent;
+        order[i] = orderInParent;
 
         // Load JSON 
         rapidjson_flax::Document document;
@@ -1637,7 +1637,6 @@ bool Actor::FromBytes(const Span<byte>& data, Array<Actor*>& output, ISerializeM
         // Order in parent
         int32 orderInParent;
         stream.ReadInt32(&orderInParent);
-        order.Add(orderInParent);
 
         // Load JSON 
         rapidjson_flax::Document document;
diff --git a/Source/Engine/UI/GUI/ContainerControl.cs b/Source/Engine/UI/GUI/ContainerControl.cs
index 57d2fb528..3519469a2 100644
--- a/Source/Engine/UI/GUI/ContainerControl.cs
+++ b/Source/Engine/UI/GUI/ContainerControl.cs
@@ -249,6 +249,8 @@ namespace FlaxEngine.GUI
         internal void ChangeChildIndex(Control child, int newIndex)
         {
             int oldIndex = _children.IndexOf(child);
+            if (oldIndex == newIndex)
+                return;
             _children.RemoveAt(oldIndex);
 
             // Check if index is invalid