diff -r d28a51dd9da6 -r 839a6e284545 src/Pure/PIDE/resources.ML
--- a/src/Pure/PIDE/resources.ML	Tue Sep 07 21:16:22 2021 +0200
+++ b/src/Pure/PIDE/resources.ML	Tue Sep 07 21:47:50 2021 +0200
@@ -168,7 +168,7 @@
 fun check_session ctxt arg =
   Completion.check_item "session"
     (fn (name, {pos, serial}) =>
-      Position.make_entity_markup false serial Markup.sessionN (name, pos))
+      Position.make_entity_markup {def = false} serial Markup.sessionN (name, pos))
     (get_session_base1 #session_positions) ctxt arg;
 
 fun session_chapter name =