tuned signature;

--- a/src/Pure/PIDE/document.scala	Thu Dec 28 22:53:45 2017 +0100
+++ b/src/Pure/PIDE/document.scala	Thu Dec 28 23:10:30 2017 +0100
@@ -120,6 +120,7 @@
       def path: Path = Path.explode(File.standard_path(node))
 
       def is_bibtex: Boolean = Bibtex.is_bibtex(node)
+      def is_bibtex_theory: Boolean = Bibtex.is_bibtex(theory)
 
       def is_theory: Boolean = theory.nonEmpty
 

--- a/src/Pure/PIDE/resources.scala	Thu Dec 28 22:53:45 2017 +0100
+++ b/src/Pure/PIDE/resources.scala	Thu Dec 28 23:10:30 2017 +0100
@@ -189,7 +189,7 @@
   }
 
   def is_hidden(name: Document.Node.Name): Boolean =
-    !name.is_theory || name.theory == Sessions.root_name || Bibtex.is_bibtex_theory(name)
+    !name.is_theory || name.theory == Sessions.root_name || name.is_bibtex_theory
 
 
   /* blobs */

--- a/src/Pure/Thy/bibtex.scala	Thu Dec 28 22:53:45 2017 +0100
+++ b/src/Pure/Thy/bibtex.scala	Thu Dec 28 23:10:30 2017 +0100
@@ -134,7 +134,6 @@
   /* bibtex files */
 
   def is_bibtex(name: String): Boolean = name.endsWith(".bib")
-  def is_bibtex_theory(name: Document.Node.Name): Boolean = is_bibtex(name.theory)
 
   private val node_suffix: String = "bibtex_file"
 

--- a/src/Tools/VSCode/src/document_model.scala	Thu Dec 28 22:53:45 2017 +0100
+++ b/src/Tools/VSCode/src/document_model.scala	Thu Dec 28 23:10:30 2017 +0100
@@ -59,7 +59,7 @@
 
   def init(session: Session, editor: Server.Editor, node_name: Document.Node.Name): Document_Model =
     Document_Model(session, editor, node_name, Content.empty,
-      node_required = Bibtex.is_bibtex_theory(node_name))
+      node_required = node_name.is_bibtex_theory)
 }
 
 sealed case class Document_Model(

--- a/src/Tools/jEdit/src/document_model.scala	Thu Dec 28 22:53:45 2017 +0100
+++ b/src/Tools/jEdit/src/document_model.scala	Thu Dec 28 23:10:30 2017 +0100
@@ -385,7 +385,7 @@
     file.foreach(PIDE.plugin.file_watcher.register_parent(_))
 
     val content = Document_Model.File_Content(text)
-    val node_required1 = node_required || Bibtex.is_bibtex_theory(node_name)
+    val node_required1 = node_required || node_name.is_bibtex_theory
     File_Model(session, node_name, file, content, node_required1, last_perspective, pending_edits)
   }
 }