diff --git a/src/calibre/gui2/toc/main.py b/src/calibre/gui2/toc/main.py
index 3be48c992d..30d9770dc9 100644
--- a/src/calibre/gui2/toc/main.py
+++ b/src/calibre/gui2/toc/main.py
@@ -1021,8 +1021,7 @@ class TOCEditor(QDialog):  # {{{
         l.addWidget(s)
         self.loading_widget = lw = QWidget(self)
         s.addWidget(lw)
-        ll = self.ll = QVBoxLayout()
-        lw.setLayout(ll)
+        ll = self.ll = QVBoxLayout(lw)
         self.pi = pi = ProgressIndicator()
         pi.setDisplaySize(QSize(200, 200))
         pi.startAnimation()