amended last_common, if that happens to the very last entry (important to load HOL/Auth, for example);
clarified touch_node: reset result explicitly;

--- a/src/Pure/PIDE/document.ML	Thu Sep 01 22:29:57 2011 +0200
+++ b/src/Pure/PIDE/document.ML	Thu Sep 01 23:08:42 2011 +0200
@@ -112,7 +112,8 @@
 fun map_entries f =
   map_node (fn (touched, header, perspective, entries, last_exec, result) =>
     (touched, header, perspective, f entries, last_exec, result));
-fun iterate_entries start f (Node {entries, ...}) = Entries.iterate start f entries;
+fun get_entries (Node {entries, ...}) = entries;
+fun iterate_entries start f = Entries.iterate start f o get_entries;
 
 fun get_last_exec (Node {last_exec, ...}) = last_exec;
 fun set_last_exec last_exec =
@@ -183,8 +184,9 @@
 
 fun touch_node name nodes =
   fold (fn desc =>
-      update_node desc (set_touched true) #>
-      desc <> name ? update_node desc (map_entries (reset_after NONE)))
+      update_node desc
+        (set_touched true #>
+          desc <> name ? (map_entries (reset_after NONE) #> set_result no_result)))
     (Graph.all_succs nodes [name]) nodes;
 
 in
@@ -391,7 +393,10 @@
       else
         let val found' = is_none exec orelse exec <> lookup_entry node0 id
         in SOME (found', (prev, visible andalso prev <> last_visible)) end;
-  in #2 (iterate_entries NONE get_common node (false, (NONE, true))) end;
+    val (found, (common, visible)) = iterate_entries NONE get_common node (false, (NONE, true));
+    val common' = if found then common else Entries.get_after (get_entries node) common;
+    val visible' = visible andalso common' <> last_visible;
+  in (common', visible') end;
 
 fun new_exec state init command_id' (execs, exec) =
   let