#3968: fix missing update() call in end_fill().
diff --git a/Lib/lib-tk/turtle.py b/Lib/lib-tk/turtle.py
index 6bc3760..295f9f4 100644
--- a/Lib/lib-tk/turtle.py
+++ b/Lib/lib-tk/turtle.py
@@ -306,6 +306,7 @@
                                             {'fill': self._color,
                                              'smooth': smooth})
                 self._items.append(item)
+                self._canvas.update()
         self._path = []
         self._filling = flag
         if flag: