diff --git a/src/calibre/gui2/toc/main.py b/src/calibre/gui2/toc/main.py
index 6bc94f3dd9..015d2f4289 100644
--- a/src/calibre/gui2/toc/main.py
+++ b/src/calibre/gui2/toc/main.py
@@ -1194,13 +1194,15 @@ class TOCEditor(QDialog):  # {{{
 
 
 def develop():
-    from calibre.utils.webengine import setup_fake_protocol
-    setup_fake_protocol()
     from calibre.gui2 import Application
     app = Application([])
+    from calibre.utils.webengine import setup_default_profile, setup_fake_protocol
+    setup_fake_protocol()
+    setup_default_profile()
     d = TOCEditor(sys.argv[-1])
     d.start()
-    d.exec()
+    d.open()
+    app.exec()
     del app
 
 
@@ -1234,9 +1236,10 @@ def main(shm_name=None):
         setup_default_profile()
         d = TOCEditor(path, title=title, write_result_to=path + '.result')
         d.start()
-        ok = 0
-        if d.exec() == QDialog.DialogCode.Accepted:
-            ok = 1
+        # Using d.exec() causes showing the webview to hide the dialog
+        d.open()
+        app.exec()
+        ok = 1 if d.result() == QDialog.DialogCode.Accepted else 0
         s = struct.pack('>II', 2, ok)
         shm.seek(0), shm.write(s), shm.flush()
 
@@ -1246,5 +1249,4 @@ def main(shm_name=None):
 
 
 if __name__ == '__main__':
-    main(path=sys.argv[-1], title='test')
-    os.remove(sys.argv[-1] + '.lock')
+    develop()
diff --git a/src/calibre/gui2/tweak_book/boss.py b/src/calibre/gui2/tweak_book/boss.py
index ddffe49128..fb644cdd0a 100644
--- a/src/calibre/gui2/tweak_book/boss.py
+++ b/src/calibre/gui2/tweak_book/boss.py
@@ -630,8 +630,14 @@ class Boss(QObject):
         if not self.ensure_book(_('You must open a book before trying to edit the Table of Contents.')):
             return
         self.add_savepoint(_('Before: Edit Table of Contents'))
-        d = TOCEditor(title=self.current_metadata.title, parent=self.gui)
-        if d.exec() != QDialog.DialogCode.Accepted:
+        self.__current_toc_editor = d = TOCEditor(title=self.current_metadata.title, parent=self.gui)
+        d.finished.connect(self.toc_edit_finished)
+        # Using d.exec() causes showing the webview to hide the dialog
+        d.open()
+
+    def toc_edit_finished(self, retcode: int):
+        self.__current_toc_editor = None
+        if retcode != QDialog.DialogCode.Accepted:
             self.rewind_savepoint()
             return
         with BusyCursor():