diff -r bef14fa789ef -r 98b6cd12f963 src/Pure/PIDE/resources.scala
--- a/src/Pure/PIDE/resources.scala	Thu Dec 28 14:20:48 2017 +0100
+++ b/src/Pure/PIDE/resources.scala	Thu Dec 28 21:45:28 2017 +0100
@@ -189,7 +189,7 @@
   }
 
   def is_hidden(name: Document.Node.Name): Boolean =
-    !name.is_theory || name.theory == Sessions.root_name
+    !name.is_theory || name.theory == Sessions.root_name || Bibtex.is_bibtex_theory(name)
 
 
   /* blobs */