diff --git a/src/Avalonia.Animation/AnimationInstance`1.cs b/src/Avalonia.Animation/AnimationInstance`1.cs
index 468c9c93a4..1ad609bce8 100644
--- a/src/Avalonia.Animation/AnimationInstance`1.cs
+++ b/src/Avalonia.Animation/AnimationInstance`1.cs
@@ -131,7 +131,6 @@ namespace Avalonia.Animation
         private void InternalStep(TimeSpan time)
         {
             DoPlayStates();
-
             var delayEndpoint = _delay;
             var iterationEndpoint = delayEndpoint + _duration;
 
@@ -163,10 +162,7 @@ namespace Avalonia.Animation
 
             if (!_isLooping)
             {
-                if (_currentIteration > _repeatCount)
-                    DoComplete();
-
-                if (time > iterationEndpoint)
+                if ((_currentIteration > _repeatCount) || (time > iterationEndpoint))
                     DoComplete();
             }
 
diff --git a/src/Avalonia.Animation/Animator`1.cs b/src/Avalonia.Animation/Animator`1.cs
index b79e2d9342..d1a8960a10 100644
--- a/src/Avalonia.Animation/Animator`1.cs
+++ b/src/Avalonia.Animation/Animator`1.cs
@@ -1,10 +1,14 @@
-using System;
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reactive.Linq;
 using Avalonia.Animation.Utils;
 using Avalonia.Collections;
 using Avalonia.Data;
+using Avalonia.Reactive;
 
 namespace Avalonia.Animation
 {
@@ -17,7 +21,7 @@ namespace Avalonia.Animation
         /// List of type-converted keyframes.
         /// </summary>
         private readonly List<AnimatorKeyFrame> _convertedKeyframes = new List<AnimatorKeyFrame>();
- 
+
         private bool _isVerifiedAndConverted;
 
         /// <summary>
@@ -28,21 +32,17 @@ namespace Avalonia.Animation
         public Animator()
         {
             // Invalidate keyframes when changed.
-             this.CollectionChanged += delegate { _isVerifiedAndConverted = false; };
+            this.CollectionChanged += delegate { _isVerifiedAndConverted = false; };
         }
 
         /// <inheritdoc/>
         public virtual IDisposable Apply(Animation animation, Animatable control, IClock clock, IObservable<bool> match, Action onComplete)
         {
-             if (!_isVerifiedAndConverted)
+            if (!_isVerifiedAndConverted)
                 VerifyConvertKeyFrames();
 
-            return match
-                .Where(p => p)
-                .Subscribe(_ =>
-                {
-                    var timerObs = RunKeyFrames(animation, control, clock, onComplete);
-                });
+            var subject = new DisposeAnimationInstanceSubject<T>(this, animation, control, clock, onComplete);
+            return match.Subscribe(subject);
         }
 
         /// <summary>
@@ -55,7 +55,7 @@ namespace Avalonia.Animation
         /// <param name="animationTime">The time parameter, relative to the total animation time</param>
         protected (double IntraKFTime, KeyFramePair<T> KFPair) GetKFPairAndIntraKFTime(double animationTime)
         {
-            AnimatorKeyFrame firstKeyframe, lastKeyframe ;
+            AnimatorKeyFrame firstKeyframe, lastKeyframe;
             int kvCount = _convertedKeyframes.Count;
             if (kvCount > 2)
             {
@@ -121,7 +121,7 @@ namespace Avalonia.Animation
         /// <summary>
         /// Runs the KeyFrames Animation.
         /// </summary>
-        private IDisposable RunKeyFrames(Animation animation, Animatable control, IClock clock, Action onComplete)
+        internal IDisposable Run(Animation animation, Animatable control, IClock clock, Action onComplete)
         {
             var instance = new AnimationInstance<T>(
                 animation,
@@ -188,4 +188,4 @@ namespace Avalonia.Animation
             }
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/Avalonia.Animation/DisposeAnimationInstanceSubject.cs b/src/Avalonia.Animation/DisposeAnimationInstanceSubject.cs
new file mode 100644
index 0000000000..a535b30b58
--- /dev/null
+++ b/src/Avalonia.Animation/DisposeAnimationInstanceSubject.cs
@@ -0,0 +1,65 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reactive.Linq;
+using Avalonia.Animation.Utils;
+using Avalonia.Collections;
+using Avalonia.Data;
+using Avalonia.Reactive;
+
+namespace Avalonia.Animation
+{
+    /// <summary>
+    /// Manages the lifetime of animation instances as determined by its selector state.
+    /// </summary>
+    internal class DisposeAnimationInstanceSubject<T> : IObserver<bool>, IDisposable
+    {
+        private IDisposable _lastInstance;
+        private bool _lastMatch;
+        private Animator<T> _animator;
+        private Animation _animation;
+        private Animatable _control;
+        private Action _onComplete;
+        private IClock _clock;
+
+        public DisposeAnimationInstanceSubject(Animator<T> animator, Animation animation, Animatable control, IClock clock, Action onComplete)
+        {
+            this._animator = animator;
+            this._animation = animation;
+            this._control = control;
+            this._onComplete = onComplete;
+            this._clock = clock;
+        }
+
+
+        public void Dispose()
+        {
+            _lastInstance?.Dispose();
+        }
+
+        public void OnCompleted()
+        {
+        }
+
+        public void OnError(Exception error)
+        {
+            _lastInstance?.Dispose();
+        }
+
+        void IObserver<bool>.OnNext(bool matchVal)
+        {
+            if (matchVal != _lastMatch)
+            {
+                _lastInstance?.Dispose();
+                if (matchVal)
+                {
+                    _lastInstance = _animator.Run(_animation, _control, _clock, _onComplete);
+                }
+                _lastMatch = matchVal;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Avalonia.Animation/DoubleAnimator.cs b/src/Avalonia.Animation/DoubleAnimator.cs
index aeeb29a7dd..2e0ce64185 100644
--- a/src/Avalonia.Animation/DoubleAnimator.cs
+++ b/src/Avalonia.Animation/DoubleAnimator.cs
@@ -1,4 +1,7 @@
-namespace Avalonia.Animation
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Avalonia.Animation
 {
     /// <summary>
     /// Animator that handles <see cref="double"/> properties.
diff --git a/src/Avalonia.Animation/FillMode.cs b/src/Avalonia.Animation/FillMode.cs
index 001e1cdeb4..39beecf455 100644
--- a/src/Avalonia.Animation/FillMode.cs
+++ b/src/Avalonia.Animation/FillMode.cs
@@ -1,4 +1,7 @@
-namespace Avalonia.Animation
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Avalonia.Animation
 {
     public enum FillMode
     {
diff --git a/src/Avalonia.Animation/IAnimation.cs b/src/Avalonia.Animation/IAnimation.cs
index ff85535d8a..26cf4a6fd1 100644
--- a/src/Avalonia.Animation/IAnimation.cs
+++ b/src/Avalonia.Animation/IAnimation.cs
@@ -1,3 +1,6 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
 using System;
 using System.Threading.Tasks;
 
diff --git a/src/Avalonia.Animation/IAnimationSetter.cs b/src/Avalonia.Animation/IAnimationSetter.cs
index 2d22377286..9c8365ea37 100644
--- a/src/Avalonia.Animation/IAnimationSetter.cs
+++ b/src/Avalonia.Animation/IAnimationSetter.cs
@@ -1,3 +1,6 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
 namespace Avalonia.Animation
 {
     public interface IAnimationSetter
diff --git a/src/Avalonia.Animation/IAnimator.cs b/src/Avalonia.Animation/IAnimator.cs
index d0fb173c54..d09f396d70 100644
--- a/src/Avalonia.Animation/IAnimator.cs
+++ b/src/Avalonia.Animation/IAnimator.cs
@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
 using System.Collections.Generic;
 
 namespace Avalonia.Animation
diff --git a/src/Avalonia.Animation/KeyFrame.cs b/src/Avalonia.Animation/KeyFrame.cs
index 5eb0d2e901..44e39e042e 100644
--- a/src/Avalonia.Animation/KeyFrame.cs
+++ b/src/Avalonia.Animation/KeyFrame.cs
@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
 using System.Collections.Generic;
 using Avalonia.Collections;
 
diff --git a/src/Avalonia.Animation/KeyFramePair`1.cs b/src/Avalonia.Animation/KeyFramePair`1.cs
index b0622a1580..60a16d094f 100644
--- a/src/Avalonia.Animation/KeyFramePair`1.cs
+++ b/src/Avalonia.Animation/KeyFramePair`1.cs
@@ -1,3 +1,6 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
 namespace Avalonia.Animation
 {
     /// <summary>
diff --git a/src/Avalonia.Animation/PlayState.cs b/src/Avalonia.Animation/PlayState.cs
index 313d33d586..8d28f06eb1 100644
--- a/src/Avalonia.Animation/PlayState.cs
+++ b/src/Avalonia.Animation/PlayState.cs
@@ -1,4 +1,7 @@
-namespace Avalonia.Animation
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Avalonia.Animation
 {
     /// <summary>
     /// Determines the playback state of an animation.
diff --git a/src/Avalonia.Animation/PlaybackDirection.cs b/src/Avalonia.Animation/PlaybackDirection.cs
index bbce6106e1..a44dd388ae 100644
--- a/src/Avalonia.Animation/PlaybackDirection.cs
+++ b/src/Avalonia.Animation/PlaybackDirection.cs
@@ -1,4 +1,7 @@
-namespace Avalonia.Animation
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Avalonia.Animation
 {
     /// <summary>
     /// Determines the playback direction of an animation.
diff --git a/src/Avalonia.Base/Reactive/ObservableEx.cs b/src/Avalonia.Base/Reactive/ObservableEx.cs
index 5b2a39d5ff..a1ec8f9a8a 100644
--- a/src/Avalonia.Base/Reactive/ObservableEx.cs
+++ b/src/Avalonia.Base/Reactive/ObservableEx.cs
@@ -21,7 +21,7 @@ namespace Avalonia.Reactive
         {
             return new SingleValueImpl<T>(value);
         }
-
+ 
         private class SingleValueImpl<T> : IObservable<T>
         {
             private T _value;
@@ -30,7 +30,6 @@ namespace Avalonia.Reactive
             {
                 _value = value;
             }
-
             public IDisposable Subscribe(IObserver<T> observer)
             {
                 observer.OnNext(_value);
@@ -38,4 +37,4 @@ namespace Avalonia.Reactive
             }
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/Avalonia.Controls/ProgressBar.cs b/src/Avalonia.Controls/ProgressBar.cs
index 7f4b549849..a0f51099cd 100644
--- a/src/Avalonia.Controls/ProgressBar.cs
+++ b/src/Avalonia.Controls/ProgressBar.cs
@@ -37,7 +37,8 @@ namespace Avalonia.Controls
             PseudoClass<ProgressBar, Orientation>(OrientationProperty, o => o == Avalonia.Controls.Orientation.Horizontal, ":horizontal");
             PseudoClass<ProgressBar>(IsIndeterminateProperty, ":indeterminate");
 
-            ValueProperty.Changed.AddClassHandler<ProgressBar>(x => x.ValueChanged);
+            ValueProperty.Changed.AddClassHandler<ProgressBar>(x => x.UpdateIndicatorWhenPropChanged);
+            IsIndeterminateProperty.Changed.AddClassHandler<ProgressBar>(x => x.UpdateIndicatorWhenPropChanged);
         }
 
         public bool IsIndeterminate
@@ -114,9 +115,9 @@ namespace Avalonia.Controls
             }
         }
 
-        private void ValueChanged(AvaloniaPropertyChangedEventArgs e)
+        private void UpdateIndicatorWhenPropChanged(AvaloniaPropertyChangedEventArgs e)
         {
             UpdateIndicator(Bounds.Size);
         }
     }
-}
+}
\ No newline at end of file