From 0bfbf285ed8604e44d2934dcd815813140333cb0 Mon Sep 17 00:00:00 2001
From: megasys <megasys@intro.hu>
Date: Mon, 12 Jul 2021 22:02:40 +0200
Subject: [PATCH] Fix: Thumb should handle mouse capture loss

---
 src/Avalonia.Controls/Primitives/Thumb.cs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/Avalonia.Controls/Primitives/Thumb.cs b/src/Avalonia.Controls/Primitives/Thumb.cs
index 348922b71d..91141058e4 100644
--- a/src/Avalonia.Controls/Primitives/Thumb.cs
+++ b/src/Avalonia.Controls/Primitives/Thumb.cs
@@ -56,6 +56,26 @@ namespace Avalonia.Controls.Primitives
         {
         }
 
+        protected override void OnPointerCaptureLost(PointerCaptureLostEventArgs e)
+        {
+            if (_lastPoint.HasValue)
+            {
+                var ev = new VectorEventArgs
+                {
+                    RoutedEvent = DragCompletedEvent,
+                    Vector = _lastPoint.Value,
+                };
+
+                _lastPoint = null;
+
+                RaiseEvent(ev);
+            }
+
+            PseudoClasses.Remove(":pressed");
+
+            base.OnPointerCaptureLost(e);
+        }
+
         protected override void OnPointerMoved(PointerEventArgs e)
         {
             if (_lastPoint.HasValue)