diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
index 4316166343..1383a81dd6 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -906,14 +906,12 @@ namespace Avalonia.Win32
                 style ^= (WindowStyles.WS_SIZEFRAME);
             }
 
-            UnmanagedMethods.GetWindowRect(_hwnd, out var oldRect);
+            var oldThickness = BorderThickness;
 
             SetWindowLong(_hwnd, (int)WindowLongParam.GWL_STYLE, (uint)style);
 
             UnmanagedMethods.GetWindowRect(_hwnd, out var windowRect);
 
-            var oldThickness = BorderThickness;
-
             Rect newRect;
 
             if (_decorated)