From 6872b2a8a46cb47eb18cdc85cdff91e7e4394db2 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Tue, 15 Jun 2021 11:53:40 +0200
Subject: [PATCH 1/2] Ensure we unsubscribe from PropertyChanged.

---
 src/Avalonia.Animation/AnimationInstance`1.cs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Avalonia.Animation/AnimationInstance`1.cs b/src/Avalonia.Animation/AnimationInstance`1.cs
index 0e1882ce75..b9ba49e510 100644
--- a/src/Avalonia.Animation/AnimationInstance`1.cs
+++ b/src/Avalonia.Animation/AnimationInstance`1.cs
@@ -46,9 +46,6 @@ namespace Avalonia.Animation
             _onCompleteAction = OnComplete;
             _interpolator = Interpolator;
             _baseClock = baseClock;
-            control.PropertyChanged += ControlPropertyChanged;
-
-            UpdateNeutralValue();
             FetchProperties();
         }
 
@@ -82,6 +79,7 @@ namespace Avalonia.Animation
             // Animation may have been stopped before it has finished.
             ApplyFinalFill();
 
+            _targetControl.PropertyChanged -= ControlPropertyChanged;
             _timerSub?.Dispose();
             _clock.PlayState = PlayState.Stop;
         }
@@ -90,6 +88,8 @@ namespace Avalonia.Animation
         {
             _clock = new Clock(_baseClock);
             _timerSub = _clock.Subscribe(Step);
+            _targetControl.PropertyChanged += ControlPropertyChanged;
+            UpdateNeutralValue();
         }
 
         public void Step(TimeSpan frameTick)

From 038805bb26c74f8896093fb0204c73082de34268 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 16 Jun 2021 17:23:48 +0200
Subject: [PATCH 2/2] Cache property changed delegate.

---
 src/Avalonia.Animation/AnimationInstance`1.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Animation/AnimationInstance`1.cs b/src/Avalonia.Animation/AnimationInstance`1.cs
index b9ba49e510..cf79640150 100644
--- a/src/Avalonia.Animation/AnimationInstance`1.cs
+++ b/src/Avalonia.Animation/AnimationInstance`1.cs
@@ -37,6 +37,7 @@ namespace Avalonia.Animation
         private IDisposable _timerSub;
         private readonly IClock _baseClock;
         private IClock _clock;
+        private EventHandler<AvaloniaPropertyChangedEventArgs> _propertyChangedDelegate;
 
         public AnimationInstance(Animation animation, Animatable control, Animator<T> animator, IClock baseClock, Action OnComplete, Func<double, T, T> Interpolator)
         {
@@ -79,7 +80,7 @@ namespace Avalonia.Animation
             // Animation may have been stopped before it has finished.
             ApplyFinalFill();
 
-            _targetControl.PropertyChanged -= ControlPropertyChanged;
+            _targetControl.PropertyChanged -= _propertyChangedDelegate;
             _timerSub?.Dispose();
             _clock.PlayState = PlayState.Stop;
         }
@@ -88,7 +89,8 @@ namespace Avalonia.Animation
         {
             _clock = new Clock(_baseClock);
             _timerSub = _clock.Subscribe(Step);
-            _targetControl.PropertyChanged += ControlPropertyChanged;
+            _propertyChangedDelegate ??= ControlPropertyChanged;
+            _targetControl.PropertyChanged += _propertyChangedDelegate;
             UpdateNeutralValue();
         }