visualize skolem and hilite (undeclared frees);
tuned colors;

--- a/src/Tools/jEdit/dist-template/etc/isabelle-jedit.css	Wed Mar 30 22:03:50 2011 +0200
+++ b/src/Tools/jEdit/dist-template/etc/isabelle-jedit.css	Wed Mar 30 22:06:25 2011 +0200
@@ -9,7 +9,7 @@
 
 .report { display: none; }
 
-.hilite { background-color: #FFFACD; }
+.hilite { background-color: #FFCC66; }
 
 .keyword { font-weight: bold; color: #009966; }
 .operator { font-weight: bold; }

--- a/src/Tools/jEdit/src/jedit/isabelle_markup.scala	Wed Mar 30 22:03:50 2011 +0200
+++ b/src/Tools/jEdit/src/jedit/isabelle_markup.scala	Wed Mar 30 22:06:25 2011 +0200
@@ -26,6 +26,7 @@
   val warning_color = new Color(255, 140, 0)
   val error_color = new Color(178, 34, 34)
   val bad_color = new Color(255, 106, 106, 100)
+  val hilite_color = new Color(255, 204, 102, 100)
 
   class Icon(val priority: Int, val icon: javax.swing.Icon)
   {
@@ -100,6 +101,7 @@
   val background1: Markup_Tree.Select[Color] =
   {
     case Text.Info(_, XML.Elem(Markup(Markup.BAD, _), _)) => bad_color
+    case Text.Info(_, XML.Elem(Markup(Markup.HILITE, _), _)) => hilite_color
   }
 
   val background2: Markup_Tree.Select[Color] =
@@ -154,7 +156,7 @@
       Markup.TFREE -> NULL,
       Markup.FREE -> MARKUP,
       Markup.TVAR -> NULL,
-      Markup.SKOLEM -> NULL,
+      Markup.SKOLEM -> COMMENT2,
       Markup.BOUND -> LABEL,
       Markup.VAR -> NULL,
       Markup.NUM -> DIGIT,