From 89684e5b94d51b432a4476d089c1f1a2df8782a6 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Thu, 17 Sep 2020 17:46:07 +0200
Subject: [PATCH] Short-circuit setting source to current value.

---
 src/Avalonia.Controls/Selection/InternalSelectionModel.cs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/Avalonia.Controls/Selection/InternalSelectionModel.cs b/src/Avalonia.Controls/Selection/InternalSelectionModel.cs
index a28e4b2785..fcdaf44166 100644
--- a/src/Avalonia.Controls/Selection/InternalSelectionModel.cs
+++ b/src/Avalonia.Controls/Selection/InternalSelectionModel.cs
@@ -63,6 +63,11 @@ namespace Avalonia.Controls.Selection
 
         private protected override void SetSource(IEnumerable? value)
         {
+            if (Source == value)
+            {
+                return;
+            }
+
             object?[]? oldSelection = null;
 
             if (Source is object && value is object)