hard-wired print mode "xsymbols" increases chance that "iff" in HOL will print symbolic arrow;

--- a/src/Pure/System/isabelle_process.ML	Tue Jul 05 21:32:48 2011 +0200
+++ b/src/Pure/System/isabelle_process.ML	Tue Jul 05 21:53:59 2011 +0200
@@ -173,8 +173,10 @@
     val _ = quick_and_dirty := true;
     val _ = Goal.parallel_proofs := 0;
     val _ = Context.set_thread_data NONE;
-    val _ = Unsynchronized.change print_mode
-      (fold (update op =) [isabelle_processN, Keyword.keyword_statusN, Pretty.symbolicN]);
+    val _ =
+      Unsynchronized.change print_mode
+        (fold (update op =)
+          [Symbol.xsymbolsN, isabelle_processN, Keyword.keyword_statusN, Pretty.symbolicN]);
 
     val in_stream = setup_channels in_fifo out_fifo;
     val _ = Keyword.status ();

--- a/src/Tools/jEdit/etc/settings	Tue Jul 05 21:32:48 2011 +0200
+++ b/src/Tools/jEdit/etc/settings	Tue Jul 05 21:53:59 2011 +0200
@@ -10,7 +10,7 @@
 
 JEDIT_STYLE_SHEETS="$ISABELLE_HOME/etc/isabelle.css:$JEDIT_HOME/etc/isabelle-jedit.css:$ISABELLE_HOME_USER/etc/isabelle.css:$ISABELLE_HOME_USER/etc/isabelle-jedit.css"
 
-ISABELLE_JEDIT_OPTIONS="-m xsymbols -m no_brackets -m no_type_brackets"
+ISABELLE_JEDIT_OPTIONS="-m no_brackets -m no_type_brackets"
 
 ISABELLE_TOOLS="$ISABELLE_TOOLS:$JEDIT_HOME/lib/Tools"