From 3b93e72d45c11bed994142c37da525b763f633c0 Mon Sep 17 00:00:00 2001
From: Jumar Macato <hikari.netto23@gmail.com>
Date: Tue, 14 May 2019 20:24:09 +0800
Subject: [PATCH] Dont initialize transition instance dictionary on objects
 without Transitions on it.

---
 src/Avalonia.Animation/Animatable.cs | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/Avalonia.Animation/Animatable.cs b/src/Avalonia.Animation/Animatable.cs
index 445c490b4b..3a3d00b94a 100644
--- a/src/Avalonia.Animation/Animatable.cs
+++ b/src/Avalonia.Animation/Animatable.cs
@@ -36,16 +36,27 @@ namespace Avalonia.Animation
 
         private Transitions _transitions;
 
-        private Dictionary<AvaloniaProperty, IDisposable> _previousTransitions
-          = new Dictionary<AvaloniaProperty, IDisposable>();
+        private Dictionary<AvaloniaProperty, IDisposable> _previousTransitions;
 
         /// <summary>
         /// Gets or sets the property transitions for the control.
         /// </summary>
         public Transitions Transitions
         {
-            get { return _transitions ?? (_transitions = new Transitions()); }
-            set { SetAndRaise(TransitionsProperty, ref _transitions, value); }
+            get
+            {
+                if (_transitions == null)
+                    _transitions = new Transitions();
+
+                if (_previousTransitions == null)
+                    _previousTransitions = new Dictionary<AvaloniaProperty, IDisposable>();
+
+                return _transitions;
+            }
+            set
+            {
+                SetAndRaise(TransitionsProperty, ref _transitions, value);
+            }
         }
 
         /// <summary>
@@ -55,7 +66,7 @@ namespace Avalonia.Animation
         /// <param name="e">The event args.</param>
         protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs e)
         {
-            if (e.Priority != BindingPriority.Animation && Transitions != null)
+            if (e.Priority != BindingPriority.Animation && Transitions != null && _previousTransitions != null)
             {
                 var match = Transitions.FirstOrDefault(x => x.Property == e.Property);