Fix top pane size is not saved on tool close

ILSpy/MainWindow.xaml.cs

@@ -849,7 +849,7 @@ namespace ICSharpCode.ILSpy
 			sessionSettings.WindowBounds = this.RestoreBounds;
 			sessionSettings.SplitterPosition = leftColumn.Width.Value / (leftColumn.Width.Value + rightColumn.Width.Value);
 			if (topPane.Visibility == Visibility.Visible)
-				sessionSettings.BottomPaneSplitterPosition = topPaneRow.Height.Value / (topPaneRow.Height.Value + textViewRow.Height.Value);
+				sessionSettings.TopPaneSplitterPosition = topPaneRow.Height.Value / (topPaneRow.Height.Value + textViewRow.Height.Value);
 			if (bottomPane.Visibility == Visibility.Visible)
 				sessionSettings.BottomPaneSplitterPosition = bottomPaneRow.Height.Value / (bottomPaneRow.Height.Value + textViewRow.Height.Value);
 			sessionSettings.Save();