From 739eaa009e5b858918e4b4ef212de97c152ff368 Mon Sep 17 00:00:00 2001
From: Kit Yan Choi <kchoi@enthought.com>
Date: Tue, 12 May 2020 16:47:22 +0100
Subject: [PATCH] Add comment related to #1047

---
 traits/observers/_trait_added_observer.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/traits/observers/_trait_added_observer.py b/traits/observers/_trait_added_observer.py
index 9a8de4d58..a91efa5fb 100644
--- a/traits/observers/_trait_added_observer.py
+++ b/traits/observers/_trait_added_observer.py
@@ -211,6 +211,9 @@ def observer_change_handler(event, graph, handler, target, dispatcher):
             dispatcher=dispatcher,
             remove=False,
         )
+        # Added notifiers cannot be removed because the reverse action
+        # of ``add_trait`` does not fire a change event
+        # see enthought/traits#1047
 
     def iter_extra_graphs(self, graph):
         """ Yield new ObserverGraph to be contributed by this observer.