diff --git a/OpenUtau/Views/PianoRollWindow.axaml b/OpenUtau/Views/PianoRollWindow.axaml
index 375e1103d..4cd9c01a1 100644
--- a/OpenUtau/Views/PianoRollWindow.axaml
+++ b/OpenUtau/Views/PianoRollWindow.axaml
@@ -16,7 +16,7 @@
   </Window.Styles>
   <Grid>
   <Border>
-    <Grid VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Margin="{Binding $parent[1].WindowDecorationMargin}">
+    <Grid VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Margin="{Binding $parent[2].WindowDecorationMargin}">
       <Grid.RowDefinitions>
         <RowDefinition Height="24"/>
         <RowDefinition Height="24"/>