diff -r 6f2943e34d60 -r 4f264fdf8d0e src/Pure/Thy/thy_syntax.scala
--- a/src/Pure/Thy/thy_syntax.scala	Wed Aug 24 23:20:05 2011 +0200
+++ b/src/Pure/Thy/thy_syntax.scala	Thu Aug 25 11:27:37 2011 +0200
@@ -101,7 +101,7 @@
 
   def command_perspective(node: Document.Node, perspective: Text.Perspective): Command.Perspective =
   {
-    if (perspective.isEmpty) Nil
+    if (perspective.is_empty) Nil
     else {
       val result = new mutable.ListBuffer[Command]
       @tailrec
@@ -120,8 +120,7 @@
           case _ =>
         }
       }
-      val perspective_range = Text.Range(perspective.head.start, perspective.last.stop)
-      check_ranges(perspective, node.command_range(perspective_range).toStream)
+      check_ranges(perspective.ranges, node.command_range(perspective.range).toStream)
       result.toList
     }
   }