--- a/light9/curvecalc/curveview.py	Fri Jun 14 05:30:45 2013 +0000
+++ b/light9/curvecalc/curveview.py	Fri Jun 14 18:08:07 2013 +0000
@@ -1142,6 +1142,7 @@
             self.add_curve(c) 
 
         dispatcher.connect(self.add_curve, "add_curve", sender=self.curveset)
+        dispatcher.connect(self.set_featured_curves, "set_featured_curves")
         
         self.newcurvename = gtk.EntryBuffer("", 0)
 
@@ -1158,6 +1159,18 @@
         dispatcher.send("all curves lose selection")
         self.curvesVBox.get_parent().grab_focus()
 
+    def curveRow_from_name(self, name):
+        for cr in self.allCurveRows:
+            if cr.name == name:
+                return cr
+        raise ValueError("couldn't find curveRow named %r" % name)
+
+    def set_featured_curves(self, curveNames):
+        """bring these curves to the top of the stack"""
+        for n in curveNames[::-1]:
+            self.curvesVBox.reorder_child(self.curveRow_from_name(n).box,
+                                          gtk.PACK_START)
+        
     def onKeyPress(self, widget, event):
         if not self.live: # workaround for old instances living past reload()
             return

--- a/light9/curvecalc/subterm.py	Fri Jun 14 05:30:45 2013 +0000
+++ b/light9/curvecalc/subterm.py	Fri Jun 14 18:08:07 2013 +0000
@@ -110,6 +110,17 @@
                 dispatcher.send("expr_error", sender=self.uri, exc=repr(e))
                 return Submaster.Submaster(name='Error: %s' % str(e), levels={})
 
+    def curves_used_by_expr(self):
+        """names of curves that are (maybe) used in this expression"""
+
+        with self.graph.currentState(tripleFilter=(self.uri, None, None)) as current:
+            expr = current.value(self.uri, L9['expression'])
+
+        used = []
+        for name in self.curveset.curveNamesInOrder():
+            if name in expr:
+                used.append(name)
+        return used
 
     def eval(self, current, t):
         """current graph is being passed as an optimization. It should be

--- a/light9/curvecalc/subtermview.py	Fri Jun 14 05:30:45 2013 +0000
+++ b/light9/curvecalc/subtermview.py	Fri Jun 14 18:08:07 2013 +0000
@@ -9,9 +9,10 @@
 keep = []
 
 class Subexprview(object):
-    def __init__(self, graph, ownerSubterm, saveContext):
+    def __init__(self, graph, ownerSubterm, saveContext, curveset):
         self.graph, self.ownerSubterm = graph, ownerSubterm
         self.saveContext = saveContext
+        self.curveset = curveset
 
         self.box = gtk.HBox()
 
@@ -27,9 +28,20 @@
         self.entryBuffer.connect("deleted-text", self.entry_changed)
         self.entryBuffer.connect("inserted-text", self.entry_changed)
 
+        self.entry.connect("focus-in-event", self.onFocus)
+        
         dispatcher.connect(self.exprError, "expr_error", sender=self.ownerSubterm)
         keep.append(self.__dict__)
 
+    def onFocus(self, *args):
+        curveNames = self.curveset.curveNamesInOrder()
+        currentExpr = self.entryBuffer.get_text()
+
+        usedCurves = [n for n in curveNames if n in currentExpr]
+        usedCurves.sort()
+        
+        dispatcher.send("set_featured_curves", curveNames=usedCurves)
+        
     def exprError(self, exc):
         self.error.set_text(str(exc))
         
@@ -51,7 +63,7 @@
     """
     has .label and .exprView widgets for you to put in a table
     """
-    def __init__(self, st):
+    def __init__(self, st, curveset):
         self.subterm = st
         self.graph = st.graph
 
@@ -63,7 +75,7 @@
                             actions=gtk.gdk.ACTION_COPY)
         self.label.connect("drag-data-received", self.onDataReceivedOnLabel)
         
-        sev = Subexprview(self.graph, self.subterm.uri, self.subterm.saveContext)
+        sev = Subexprview(self.graph, self.subterm.uri, self.subterm.saveContext, curveset)
         self.exprView = sev.box
 
     def onDataReceivedOnLabel(self, widget, context, x, y, selection,
@@ -87,7 +99,7 @@
         self.label.set_text(label)
 
 def add_one_subterm(subterm, curveset, master, show=False):
-    stv = Subtermview(subterm)
+    stv = Subtermview(subterm, curveset)
     
     y = master.get_property('n-rows')
     master.attach(stv.label, 0, 1, y, y + 1, xoptions=0, yoptions=0)