From 9e9565f40f5222b477cdc4607c5f3ec2eab1f430 Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Wed, 20 May 2020 10:39:00 -0300
Subject: [PATCH] fix border only margin.

---
 src/Windows/Avalonia.Win32/WindowImpl.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
index dd9a350b85..2cf87c1556 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -861,9 +861,14 @@ namespace Avalonia.Win32
 
                 if (!_isFullScreenActive)
                 {
+                    var margin = newProperties.Decorations == SystemDecorations.BorderOnly ? 1 : 0;
+
                     var margins = new MARGINS
                     {
-                        cyBottomHeight = newProperties.Decorations == SystemDecorations.BorderOnly ? 1 : 0
+                        cyBottomHeight = margin,
+                        cxRightWidth = margin,
+                        cxLeftWidth = margin,
+                        cyTopHeight = margin
                     };
 
                     DwmExtendFrameIntoClientArea(_hwnd, ref margins);