From 172de036be36360e996f2d2e5b201bde8b122b76 Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Tue, 5 May 2020 14:15:21 -0300
Subject: [PATCH] fix glitch with window decorations transitioning from
 fullscreen to maximized.

---
 src/Windows/Avalonia.Win32/WindowImpl.cs | 34 ++++++++++++------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
index 15261fe1c4..549a568fa2 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -801,6 +801,11 @@ namespace Avalonia.Win32
                 SetStyle(style);
             }
 
+            if (oldProperties.IsFullScreen != newProperties.IsFullScreen)
+            {
+                SetFullScreen(newProperties.IsFullScreen);
+            }
+
             if ((oldProperties.Decorations != newProperties.Decorations) || forceChanges)
             {
                 var style = GetStyle();
@@ -816,22 +821,22 @@ namespace Avalonia.Win32
                     style &= ~fullDecorationFlags;
                 }
 
-                var margins = new MARGINS
-                {
-                    cyBottomHeight = newProperties.Decorations == SystemDecorations.BorderOnly ? 1 : 0
-                };
-
-                DwmExtendFrameIntoClientArea(_hwnd, ref margins);
-
-                GetClientRect(_hwnd, out var oldClientRect);
-                var oldClientRectOrigin = new POINT();
-                ClientToScreen(_hwnd, ref oldClientRectOrigin);
-                oldClientRect.Offset(oldClientRectOrigin);
-
                 SetStyle(style);
 
                 if (!_isFullScreenActive)
                 {
+                    var margins = new MARGINS
+                    {
+                        cyBottomHeight = newProperties.Decorations == SystemDecorations.BorderOnly ? 1 : 0
+                    };
+
+                    DwmExtendFrameIntoClientArea(_hwnd, ref margins);
+
+                    GetClientRect(_hwnd, out var oldClientRect);
+                    var oldClientRectOrigin = new POINT();
+                    ClientToScreen(_hwnd, ref oldClientRectOrigin);
+                    oldClientRect.Offset(oldClientRectOrigin);
+
                     var newRect = oldClientRect;
 
                     if (newProperties.Decorations == SystemDecorations.Full)
@@ -844,11 +849,6 @@ namespace Avalonia.Win32
                         SetWindowPosFlags.SWP_FRAMECHANGED);
                 }
             }
-
-            if (oldProperties.IsFullScreen != newProperties.IsFullScreen)
-            {
-                SetFullScreen(newProperties.IsFullScreen);
-            }
         }
 
 #if USE_MANAGED_DRAG