From 30e006ac78d91b49eddd0ad9368ccff216e58c32 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Sat, 13 Apr 2019 16:26:43 +0200
Subject: [PATCH] Throw an exception when trying to re-show closed window.

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

diff --git a/src/Avalonia.Controls/Window.cs b/src/Avalonia.Controls/Window.cs
index c8e09b8f9c..6c3517af62 100644
--- a/src/Avalonia.Controls/Window.cs
+++ b/src/Avalonia.Controls/Window.cs
@@ -373,6 +373,11 @@ namespace Avalonia.Controls
         /// </summary>
         public override void Show()
         {
+            if (PlatformImpl == null)
+            {
+                throw new InvalidOperationException("Cannot re-show a closed window.");
+            }
+
             if (IsVisible)
             {
                 return;