From 2661e939b1d548fcb4116d025c4f7e87f4684a83 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 15 May 2019 14:10:45 +0200
Subject: [PATCH] Reset dirty rects before calling SceneInvalidated.

When cleared after calling `SceneInvalidated`, any control invalidated during `SceneInvalidated` was be lost.

Fixes #2518.
---
 src/Avalonia.Visuals/Rendering/DeferredRenderer.cs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
index 5d1c66f872..c83a8436b4 100644
--- a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
@@ -528,6 +528,8 @@ namespace Avalonia.Rendering
                     oldScene?.Dispose();
                 }
 
+                _dirty.Clear();
+
                 if (SceneInvalidated != null)
                 {
                     var rect = new Rect();
@@ -540,10 +542,9 @@ namespace Avalonia.Rendering
                         }
                     }
 
+                    System.Diagnostics.Debug.WriteLine("Invalidated " + rect);
                     SceneInvalidated(this, new SceneInvalidatedEventArgs((IRenderRoot)_root, rect));
                 }
-
-                _dirty.Clear();
             }
             else
             {