From b7efe2037c5ac3cb9976e95d36b2285ec95d0306 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Tue, 8 Oct 2019 00:35:20 +0200
Subject: [PATCH] Only set SizeToContent for non-set width/height.

Always setting `SizeToContext = WidthAndHeight` was causing `Grid` to default to `Auto` sizing for `Star` rows/columns at design-time.

Fixes #2862
---
 src/Avalonia.DesignerSupport/DesignWindowLoader.cs | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/Avalonia.DesignerSupport/DesignWindowLoader.cs b/src/Avalonia.DesignerSupport/DesignWindowLoader.cs
index a7d4b96974..f3bb0edce5 100644
--- a/src/Avalonia.DesignerSupport/DesignWindowLoader.cs
+++ b/src/Avalonia.DesignerSupport/DesignWindowLoader.cs
@@ -69,7 +69,17 @@ namespace Avalonia.DesignerSupport
                 }
 
                 if (!window.IsSet(Window.SizeToContentProperty))
-                    window.SizeToContent = SizeToContent.WidthAndHeight;
+                {
+                    if (double.IsNaN(window.Width))
+                    {
+                        window.SizeToContent |= SizeToContent.Width;
+                    }
+
+                    if (double.IsNaN(window.Height))
+                    {
+                        window.SizeToContent |= SizeToContent.Height;
+                    }
+                }
             }
             window.Show();
             Design.ApplyDesignModeProperties(window, control);