diff --git a/src/lay/lay/layMainWindow.h b/src/lay/lay/layMainWindow.h
index 56c3dd597..dee59857d 100644
--- a/src/lay/lay/layMainWindow.h
+++ b/src/lay/lay/layMainWindow.h
@@ -95,6 +95,7 @@ class ProgressWidget;
 class LAY_PUBLIC MainWindow
   : public QMainWindow,
     public tl::Object,
+    public gsi::ObjectBase,
     public lay::DispatcherDelegate
 {
 Q_OBJECT