src/Tools/VSCode/src/vscode_resources.scala

 
         /* auxiliary files */
 
         val stable_tip_version =
           if (st.models.forall(entry => entry._2.is_stable))
-            session.current_state().stable_tip_version
+            session.get_state().stable_tip_version
           else None
 
         val aux_files =
           stable_tip_version match {
             case Some(version) => undefined_blobs(version.nodes)