diff --git a/src/calibre/gui2/tweak_book/preview.py b/src/calibre/gui2/tweak_book/preview.py
index af93a8f347..90906c9d45 100644
--- a/src/calibre/gui2/tweak_book/preview.py
+++ b/src/calibre/gui2/tweak_book/preview.py
@@ -285,6 +285,7 @@ class Preview(QWidget):
 
     def refresh(self):
         if self.current_name:
+            self.refresh_timer.stop()
             # This will check if the current html has changed in its editor,
             # and re-parse it if so
             parse_worker.add_request(self.current_name)