proper display_name;

--- a/src/Pure/context.ML	Mon Apr 10 21:43:21 2017 +0200
+++ b/src/Pure/context.ML	Mon Apr 10 22:59:29 2017 +0200
@@ -165,7 +165,9 @@
 val finished = ~1;
 
 fun display_name thy_id =
-  let val {name, stage} = history_of_id thy_id
+  let
+    val {name = long_name, stage} = history_of_id thy_id;
+    val name = Long_Name.base_name long_name;
   in if stage = finished then name else name ^ ":" ^ string_of_int stage end;
 
 fun display_names thy =