--- a/hgext3rd/topic/destination.py	Thu Apr 18 12:40:53 2019 +0200
+++ b/hgext3rd/topic/destination.py	Thu Apr 18 12:41:41 2019 +0200
@@ -78,6 +78,8 @@
     return node, movemark, None
 
 def desthistedit(orig, ui, repo):
+    if not common.hastopicext(repo):
+        return None
     if not (ui.config('histedit', 'defaultrev', None) is None
             and repo.currenttopic):
         return orig(ui, repo)