From 60c0a44a8737da790d68c73f9d8036b72396aad3 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Tue, 8 Sep 2020 10:51:52 +0200
Subject: [PATCH] Clean up EffectiveViewportChanged earlier.

Clean up the `EffectiveViewportChanged` subscriptions before calling `OnDetachedFromVisualTree` so that (un)subscribing to the `EffectiveViewportChanged`  event in `OnDetachedFromVisualTree` doesn't cause a leak.
---
 src/Avalonia.Layout/Layoutable.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Layout/Layoutable.cs b/src/Avalonia.Layout/Layoutable.cs
index e62e22f8ec..aca2965ea6 100644
--- a/src/Avalonia.Layout/Layoutable.cs
+++ b/src/Avalonia.Layout/Layoutable.cs
@@ -758,8 +758,6 @@ namespace Avalonia.Layout
 
         protected override void OnDetachedFromVisualTreeCore(VisualTreeAttachmentEventArgs e)
         {
-            base.OnDetachedFromVisualTreeCore(e);
-
             if (e.Root is ILayoutRoot r)
             {
                 if (_layoutUpdated is object)
@@ -772,6 +770,8 @@ namespace Avalonia.Layout
                     r.LayoutManager.UnregisterEffectiveViewportListener(this);
                 }
             }
+
+            base.OnDetachedFromVisualTreeCore(e);
         }
 
         /// <summary>