Fixed viewport not updating on doc change

src/PixiDocks

@@ -1 +1 @@
-Subproject commit 68dafe4747a6cead83359ede8e0bbc65cdda02a8
+Subproject commit 42b1f6939f7b56726ed6aba09e49897b507f569d

src/PixiEditor/Views/Main/ViewportControls/FixedViewport.axaml.cs

@@ -128,6 +128,8 @@ internal partial class FixedViewport : UserControl, INotifyPropertyChanged
         {
             newDoc.SizeChanged += viewport.DocSizeChanged;
         }
+        
+        viewport.ForceRefreshFinalImage();
     }
 
     private void DocSizeChanged(object? sender, DocumentSizeChangedEventArgs e)