FreeFormTool: fixed AttributeError: 'NoneType' object has no attribute 'points'

Author: PierreRaybaut

plotpy/tools/shape.py

@@ -238,7 +238,8 @@ def cancel_point(self, filter, event) -> None:
             event: The triggering event.
         """
         super().cancel_point(filter, event)
-        self.shape.closed = len(self.shape.points) > 2
+        if self.shape is not None:
+            self.shape.closed = len(self.shape.points) > 2
 
     def mouse_press(self, filter, event) -> None:
         """