diff --git a/collects/macro-debugger/emit.rkt b/collects/macro-debugger/emit.rkt
new file mode 100644
index 0000000..e5ea883
--- /dev/null
+++ b/collects/macro-debugger/emit.rkt
@@ -0,0 +1,32 @@
+#lang racket/base
+(require racket/contract/base)
+
+(provide/contract
+ [emit-remark
+  (->* () (#:unmark? any/c) #:rest (listof (or/c string? syntax?))
+       any)]
+ [emit-local-step
+  (-> syntax? syntax? #:id identifier? any)])
+
+(define current-expand-observe
+  (dynamic-require ''#%expobs 'current-expand-observe))
+
+(define (emit-remark #:unmark? [unmark? #t] . args)
+  (let ([observe (current-expand-observe)])
+    (when observe
+      (let ([args
+             (if unmark?
+                 (for/list ([arg (in-list args)])
+                   (if (syntax? arg)
+                       (syntax-local-introduce arg)
+                       arg))
+                 args)])
+        (observe 'local-remark args)))))
+
+(define (emit-local-step before after #:id id)
+  (let ([observe (current-expand-observe)])
+    (when observe
+      (observe 'local-artificial-step
+               (list (list id)
+                     before (syntax-local-introduce before)
+                     (syntax-local-introduce after) after)))))
diff --git a/collects/macro-debugger/expand.rkt b/collects/macro-debugger/expand.rkt
index 48d4c22..b34cb03 100644
--- a/collects/macro-debugger/expand.rkt
+++ b/collects/macro-debugger/expand.rkt
@@ -1,8 +1,8 @@
-#lang scheme/base
-(require scheme/contract
-         "model/trace.ss"
-         "model/reductions-config.ss"
-         "model/reductions.ss")
+#lang racket/base
+(require racket/contract
+         "model/trace.rkt"
+         "model/reductions-config.rkt"
+         "model/reductions.rkt")
 
 (provide/contract
  [expand-only 
diff --git a/collects/macro-debugger/info.rkt b/collects/macro-debugger/info.rkt
index 55db6ff..0a5856f 100644
--- a/collects/macro-debugger/info.rkt
+++ b/collects/macro-debugger/info.rkt
@@ -1,5 +1,5 @@
 #lang setup/infotab
 
-(define tools '(["tool.ss"]))
+(define tools '(["tool.rkt"]))
 (define tool-names '("Macro Stepper"))
 (define scribblings '(("macro-debugger.scrbl" () (tool-library))))
diff --git a/collects/macro-debugger/macro-debugger.scrbl b/collects/macro-debugger/macro-debugger.scrbl
index f80a66f..051ce25 100644
--- a/collects/macro-debugger/macro-debugger.scrbl
+++ b/collects/macro-debugger/macro-debugger.scrbl
@@ -4,6 +4,7 @@
           scribble/eval
           (for-label scheme/base
                      macro-debugger/expand
+                     macro-debugger/emit
                      macro-debugger/stepper
                      macro-debugger/stepper-text
                      macro-debugger/syntax-browser
@@ -101,6 +102,58 @@ thing as the original syntax.
                (lambda (id) (memq (syntax-e id) '(or #%app))))))
 }
 
+
+@section{Macro stepper API for macros}
+
+@defmodule[macro-debugger/emit]
+
+Macros can explicitly send information to a listening macro stepper by
+using the procedures in this module.
+
+@defproc[(emit-remark [fragment (or/c syntax? string?)] ...
+                      [#:unmark? unmark? boolean? #t])
+         void?]{
+
+Emits an event to the macro stepper (if one is listening) containing
+the given strings and syntax objects. The macro stepper displays a
+remark by printing the strings and syntax objects above a rendering of
+the macro's context. The remark is only displayed if the macro that
+emits it is considered transparent by the hiding policy.
+
+By default, syntax objects in remarks have the transformer's mark
+applied (using @scheme[syntax-local-introduce]) so that their
+appearance in the macro stepper matches their appearance after the
+transformer returns. Unmarking is suppressed if @scheme[unmark?] is
+@scheme[#f].
+
+@schemeblock[
+(define-syntax (mymac stx)
+  (syntax-case stx ()
+    [(_ x y)
+     (emit-remark "I got some arguments!"
+                  #'x
+                  "and"
+                  #'y)
+     #'(list 'x 'y)]))
+(mymac 37 (+ 1 2))
+]
+
+(Run the fragment above in the macro stepper.)
+
+}
+
+@defproc[(emit-local-step [before syntax?] [after syntax?]
+                          [#:id id identifier?])
+         void?]{
+
+Emits an event that simulates a local expansion step from
+@scheme[before] to @scheme[after].
+
+The @scheme[id] argument acts as the step's ``macro'' for the purposes
+of macro hiding.
+
+}
+
 @section{Macro stepper text interface}
 
 @defmodule[macro-debugger/stepper-text]
diff --git a/collects/macro-debugger/model/context.rkt b/collects/macro-debugger/model/context.rkt
index c385aff..8d6073d 100644
--- a/collects/macro-debugger/model/context.rkt
+++ b/collects/macro-debugger/model/context.rkt
@@ -1,5 +1,4 @@
-#lang scheme/base
-
+#lang racket/base
 (require syntax/stx)
 (provide (struct-out ref)
          (struct-out tail)
diff --git a/collects/macro-debugger/model/debug.rkt b/collects/macro-debugger/model/debug.rkt
index 3ba4ad0..1bb8157 100644
--- a/collects/macro-debugger/model/debug.rkt
+++ b/collects/macro-debugger/model/debug.rkt
@@ -1,19 +1,18 @@
-#lang scheme/base
+#lang racket/base
+(require racket/match
+         "trace.rkt"
+         "reductions.rkt"
+         "reductions-config.rkt"
+         "deriv-util.rkt"
+         "hiding-policies.rkt"
+         "deriv.rkt"
+         "steps.rkt")
 
-(require scheme/match
-         "trace.ss"
-         "reductions.ss"
-         "reductions-config.ss"
-         "deriv-util.ss"
-         "hiding-policies.ss"
-         "deriv.ss"
-         "steps.ss")
-
-(provide (all-from-out "trace.ss")
-         (all-from-out "reductions.ss")
-         (all-from-out "reductions-config.ss")
-         (all-from-out "deriv.ss")
-         (all-from-out "deriv-util.ss")
-         (all-from-out "hiding-policies.ss")
-         (all-from-out "steps.ss")
-         (all-from-out scheme/match))
+(provide (all-from-out "trace.rkt")
+         (all-from-out "reductions.rkt")
+         (all-from-out "reductions-config.rkt")
+         (all-from-out "deriv.rkt")
+         (all-from-out "deriv-util.rkt")
+         (all-from-out "hiding-policies.rkt")
+         (all-from-out "steps.rkt")
+         (all-from-out racket/match))
diff --git a/collects/macro-debugger/model/deriv-c.rkt b/collects/macro-debugger/model/deriv-c.rkt
index 09966bf..2ab5dc6 100644
--- a/collects/macro-debugger/model/deriv-c.rkt
+++ b/collects/macro-debugger/model/deriv-c.rkt
@@ -1,5 +1,4 @@
-
-#lang scheme/base
+#lang racket/base
 (provide (all-defined-out))
 
 ;; A Node(a) is:
@@ -40,6 +39,8 @@
 (define-struct local-lift-require (req expr mexpr) #:transparent)
 (define-struct local-lift-provide (prov) #:transparent)
 (define-struct local-bind (names ?1 renames bindrhs) #:transparent)
+(define-struct local-remark (contents) #:transparent)
+  ;; contents : (listof (U string syntax))
 
 ;; A PrimDeriv is one of
 (define-struct (prule base) () #:transparent)
diff --git a/collects/macro-debugger/model/deriv-parser.rkt b/collects/macro-debugger/model/deriv-parser.rkt
index 9124ea6..c24e0d2 100644
--- a/collects/macro-debugger/model/deriv-parser.rkt
+++ b/collects/macro-debugger/model/deriv-parser.rkt
@@ -1,12 +1,11 @@
-
-#lang scheme/base
-(require (for-syntax scheme/base)
+#lang racket/base
+(require (for-syntax racket/base)
          syntax/stx
-         "yacc-ext.ss"
-         "yacc-interrupted.ss"
-         "deriv.ss"
-         "deriv-util.ss"
-         "deriv-tokens.ss")
+         "yacc-ext.rkt"
+         "yacc-interrupted.rkt"
+         "deriv.rkt"
+         "deriv-util.rkt"
+         "deriv-tokens.rkt")
 (provide parse-derivation)
 
 (define (deriv-error ok? name value start end)
@@ -202,6 +201,20 @@
       (make local-bind $1 $2 $3 #f)]
      [(local-bind rename-list (? BindSyntaxes))
       (make local-bind $1 #f $2 $3)]
+     [(local-remark)
+      (make local-remark $1)]
+     [(local-artificial-step)
+      (let ([ids (list-ref $1 0)]
+            [before (list-ref $1 1)]
+            [mbefore (list-ref $1 2)]
+            [mafter (list-ref $1 3)]
+            [after (list-ref $1 4)])
+        (make local-expansion
+          before after #f mbefore
+          (make mrule mbefore mafter ids #f
+                before null after #f mafter
+                (make p:stop mafter mafter null #f))
+          #f after #f))]
      ;; -- Not really local actions, but can occur during evaluation
      ;; called 'expand' (not 'local-expand') within transformer
      [(start (? EE)) #f]
diff --git a/collects/macro-debugger/model/deriv-tokens.rkt b/collects/macro-debugger/model/deriv-tokens.rkt
index 9dc8b0d..d33e3c2 100644
--- a/collects/macro-debugger/model/deriv-tokens.rkt
+++ b/collects/macro-debugger/model/deriv-tokens.rkt
@@ -1,7 +1,6 @@
-
-#lang scheme/base
+#lang racket/base
 (require parser-tools/lex
-         "deriv.ss")
+         "deriv.rkt")
 (provide (all-defined-out))
 
 (define-tokens basic-tokens
@@ -59,6 +58,9 @@
 
    top-begin            ; identifier
    top-non-begin        ; .
+
+   local-remark         ; (listof (U string syntax))
+   local-artificial-step ; (list syntax syntax syntax syntax)
    ))
 
 (define-tokens renames-tokens
@@ -93,6 +95,8 @@
     (#f  start                   ,token-start)
     (#f  top-begin               ,token-top-begin)
     (#f  top-non-begin           ,token-top-non-begin)
+    (#f  local-remark            ,token-local-remark)
+    (#f  local-artificial-step   ,token-local-artificial-step)
 
     ;; Standard signals
     (0   visit                   ,token-visit)
diff --git a/collects/macro-debugger/model/deriv-util.rkt b/collects/macro-debugger/model/deriv-util.rkt
index 0a3c2a3..8987afb 100644
--- a/collects/macro-debugger/model/deriv-util.rkt
+++ b/collects/macro-debugger/model/deriv-util.rkt
@@ -1,11 +1,10 @@
-
-#lang scheme/base
-(require (for-syntax scheme/base)
+#lang racket/base
+(require (for-syntax racket/base)
          (for-syntax racket/private/struct-info)
-         scheme/list
-         scheme/match
+         racket/list
+         racket/match
          unstable/struct
-         "deriv.ss")
+         "deriv.rkt")
 
 (provide make
 
diff --git a/collects/macro-debugger/model/deriv.rkt b/collects/macro-debugger/model/deriv.rkt
index a7be9bd..420d6ca 100644
--- a/collects/macro-debugger/model/deriv.rkt
+++ b/collects/macro-debugger/model/deriv.rkt
@@ -1,368 +1,5 @@
-
-#lang scheme/base
-(require scheme/contract
+#lang racket/base
+(require racket/contract
          syntax/stx
-         "deriv-c.ss")
-
-(provide (all-from-out "deriv-c.ss"))
-
-#|
-
-(define (?? c) (or/c c false/c))
-
-(define (stx? x)
-  (or (syntax? x)
-      (and (pair? x) (stx? (car x)) (stx? (cdr x)))
-      (null? x)))
-
-(define (stx-list-like? x)
-  (let ([x (stx->list x)])
-    (and x (andmap syntax? x))))
-
-(define syntax/f (?? syntax?))
-(define syntaxes/c stx-list-like?)
-(define syntaxes/f (?? syntaxes/c))
-(define resolves/c (listof identifier?))
-
-(define localaction/c
-  (or/c local-expansion? local-expansion/expr? local-lift?
-        local-lift-end? local-bind?))
-
-(provide/contract
- (struct node
-         ([z1 any/c]
-          [z2 any/c]))
- (struct (deriv node)
-         ([z1 syntax?]
-          [z2 syntax/f]))
- (struct (lift-deriv deriv)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [first deriv?]
-          [lift-stx syntax?]
-          [second deriv?]))
- (struct (mrule deriv)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [transformation transformation?]
-          [next (?? deriv?)]))
- (struct (lift/let-deriv deriv)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [first deriv?]
-          [lift-stx syntax?]
-          [second deriv?]))
- (struct (transformation node)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [me1 (?? syntax?)]
-          [locals (?? (listof localaction/c))]
-          [me2 (?? syntax?)]
-          [?2 (?? exn?)]
-          [seq number?]))
- (struct (local-expansion node)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [me1 syntax?]
-          [me2 syntax/f]
-          [for-stx? boolean?]
-          [inner deriv?]))
- (struct (local-expansion/expr node)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [me1 syntax?]
-          [me2 syntax/f]
-          [for-stx? boolean?]
-          [opaque any/c]
-          [inner deriv?]))
- (struct local-lift
-         ([expr syntax?]
-          [id identifier?]))
- (struct local-lift-end
-         ([decl syntax?]))
- (struct local-bind
-         ([bindrhs bind-syntaxes?]))
- (struct (base deriv)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (prule base)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:variable prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:module prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [one-body-form? boolean?]
-          [mb (?? deriv?)]
-          [?2 (?? exn?)]
-          [body (?? deriv?)]))
- (struct (p:#%module-begin prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [pass1 (?? (listof modrule?))]
-          [pass2 (?? (listof modrule?))]
-          [?2 (?? exn?)]))
- (struct (p:define-syntaxes prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [rhs (?? deriv?)]
-          [?2 (?? exn?)]))
- (struct (p:define-values prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [rhs (?? deriv?)]))
- (struct (p:#%expression prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [inner (?? deriv?)]))
- (struct (p:if prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [full? boolean?]
-          [test (?? deriv?)]
-          [then (?? deriv?)]
-          [else (?? deriv?)]))
- (struct (p:wcm prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [key (?? deriv?)]
-          [mark (?? deriv?)]
-          [body (?? deriv?)]))
- (struct (p:set! prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [id-resolves (?? resolves/c)]
-          [rhs (?? deriv?)]))
- (struct (p:set!-macro prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [deriv (?? deriv?)]))
- (struct (p:#%app prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [tagged-stx syntax/f]
-          [lderiv (?? lderiv?)]))
- (struct (p:begin prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [lderiv (?? lderiv?)]))
- (struct (p:begin0 prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [first (?? deriv?)]
-          [lderiv (?? lderiv?)]))
- (struct (p:lambda prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [renames any/c] ;; fixme
-          [body (?? bderiv?)]))
- (struct (p:case-lambda prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [renames+bodies (listof clc?)]))
- (struct (p:let-values prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [renames any/c] ;; fixme
-          [rhss (?? (listof deriv?))]
-          [body (?? bderiv?)]))
- (struct (p:letrec-values prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [renames any/c] ;; fixme
-          [rhss (?? (listof deriv?))]
-          [body (?? bderiv?)]))
- (struct (p:letrec-syntaxes+values prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [srenames any/c] ;; fixme
-          [sbindrhss (?? (listof bind-syntaxes?))]
-          [vrenames any/c] ;; fixme
-          [vrhss (?? (listof deriv?))]
-          [body (?? bderiv?)]))
- (struct (p::STOP prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:stop p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:unknown p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:#%top p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [tagged-stx syntax/f]))
- (struct (p:#%datum p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [tagged-stx syntax/f]))
- (struct (p:quote p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:quote-syntax p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:require p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:require-for-syntax p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:require-for-template p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:provide p::STOP)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]))
- (struct (p:rename prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [renames any/c]
-          [inner (?? deriv?)]))
- (struct (p:synth prule)
-         ([z1 syntax?]
-          [z2 syntax/f]
-          [resolves resolves/c]
-          [?1 (?? exn?)]
-          [subterms (?? (listof subitem?))]
-          [?2 (?? exn?)]))
-
- (struct (lderiv node)
-         ([z1 stx?]
-          [z2 syntaxes/f]
-          [?1 (?? exn?)]
-          [derivs (?? (listof deriv?))]))
- (struct (bderiv node)
-         ([z1 stx?]
-          [z2 syntaxes/f]
-          [pass1 (?? (listof (or/c b:error? brule?)))]
-          [trans (symbols 'list 'letrec)]
-          [pass2 (?? lderiv?)]))
-
- (struct b:error
-         ([?1 exn?]))
- (struct brule
-         ([renames any/c]))
- (struct (b:expr brule)
-         ([renames any/c]
-          [head deriv?]))
- (struct (b:splice brule)
-         ([renames any/c]
-          [head deriv?]
-          [?1 (?? exn?)]
-          [tail (?? stx?)]
-          [?2 (?? exn?)]))
- (struct (b:defvals brule)
-         ([renames any/c]
-          [head deriv?]
-          [?1 (?? exn?)]))
- (struct (b:defstx brule)
-         ([renames any/c]
-          [head deriv?]
-          [?1 (?? exn?)]
-          [bindrhs (?? bind-syntaxes?)]))
-
- (struct bind-syntaxes
-         ([rhs deriv?]
-          [?1 (?? exn?)]))
-
- (struct clc
-         ([?1 (?? exn?)]
-          [renames any/c]
-          [body (?? bderiv?)]))
-
- (struct modrule ())
- (struct (mod:cons modrule)
-         ([head deriv?]))
- (struct (mod:prim modrule)
-         ([head deriv?]
-          [prim (?? deriv?)]))
- (struct (mod:skip modrule) ())
- (struct (mod:splice modrule)
-         ([head deriv?]
-          [?1 (?? exn?)]
-          [tail (?? stx?)]))
- (struct (mod:lift modrule)
-         ([head deriv?]
-          [tail syntaxes/c]))
- (struct (mod:lift-end modrule)
-         ([tail syntaxes/c]))
-
- (struct subitem ())
- (struct (s:subterm subitem)
-         ([path any/c]
-          [deriv deriv?]))
- (struct (s:rename subitem)
-         ([path any/c]
-          [before syntax?]
-          [after syntax?])))
-|#
+         "deriv-c.rkt")
+(provide (all-from-out "deriv-c.rkt"))
diff --git a/collects/macro-debugger/model/hiding-policies.rkt b/collects/macro-debugger/model/hiding-policies.rkt
index 51c1027..0be2f56 100644
--- a/collects/macro-debugger/model/hiding-policies.rkt
+++ b/collects/macro-debugger/model/hiding-policies.rkt
@@ -1,10 +1,8 @@
-
-#lang scheme/base
-(require (for-syntax scheme/base)
-         scheme/match
-         syntax/boundmap
-         "reductions-config.ss"
-         "../util/mpi.ss")
+#lang racket/base
+(require (for-syntax racket/base)
+         racket/match
+         "reductions-config.rkt"
+         "../util/mpi.rkt")
 (provide policy->predicate)
 
 ;; A Policy is one of
diff --git a/collects/macro-debugger/model/reductions-config.rkt b/collects/macro-debugger/model/reductions-config.rkt
index 35b6d1c..cb3cfcb 100644
--- a/collects/macro-debugger/model/reductions-config.rkt
+++ b/collects/macro-debugger/model/reductions-config.rkt
@@ -1,14 +1,13 @@
-#lang scheme/base
-
-(require (for-syntax scheme/base)
-         scheme/list
-         scheme/contract
-         scheme/match
-         "deriv.ss"
-         "deriv-util.ss"
-         "stx-util.ss"
-         "context.ss"
-         "steps.ss")
+#lang racket/base
+(require (for-syntax racket/base)
+         racket/list
+         racket/contract
+         racket/match
+         "deriv.rkt"
+         "deriv-util.rkt"
+         "stx-util.rkt"
+         "context.rkt"
+         "steps.rkt")
 
 (define-syntax-rule (STRICT-CHECKS form ...)
   (when #f
@@ -45,9 +44,6 @@
  [macro-policy (parameter/c (identifier? . -> . any))]
  [subterms-table (parameter/c (or/c subterms-table/c false/c))]
  [hides-flags (list-parameter/c boolean?)]
- [block-syntax-bindings (parameter/c (listof syntaxish?))]
- [block-value-bindings (parameter/c (listof syntaxish?))]
- [block-expressions (parameter/c syntaxish?)]
 
  [learn-binders ((listof identifier?) . -> . any)]
  [learn-definites ((listof identifier?) . -> . any)]
@@ -60,6 +56,9 @@
         [#:foci1 syntaxish? #:foci2 syntaxish?]
         . ->* . step?)]
  [stumble ([syntaxish? exn?] [#:focus syntaxish?] . ->* . misstep?)]
+ [walk/talk
+  (-> (or/c symbol? string?) (listof (or/c syntax? string? 'arrow))
+      remarkstep?)]
 
  [current-pass-hides? (parameterlike/c boolean?)]
 
@@ -112,13 +111,6 @@
 ;; hides-flags : (parameterof (listof (boxof boolean)))
 (define hides-flags (make-parameter null))
 
-;; block-syntax-bindings : (parameter/c (listof stx))
-;; block-value-bindings : (parameter/c (listof stx))
-;; block-expressions : (parameter/c (listof stx))
-(define block-value-bindings (make-parameter null))
-(define block-syntax-bindings (make-parameter null))
-(define block-expressions (make-parameter null))
-
 ;; lift params
 (define available-lift-stxs (make-parameter null))
 (define visible-lift-stxs (make-parameter null))
@@ -343,6 +335,11 @@
         (current-state-with stx focus)
         exn))
 
+(define (walk/talk type contents)
+  (make remarkstep type
+        (current-state-with #f null)
+        contents))
+
 (define (foci x)
   (cond [(syntax? x)
          (list x)]
diff --git a/collects/macro-debugger/model/reductions-engine.rkt b/collects/macro-debugger/model/reductions-engine.rkt
index 9c89829..f02f088 100644
--- a/collects/macro-debugger/model/reductions-engine.rkt
+++ b/collects/macro-debugger/model/reductions-engine.rkt
@@ -1,16 +1,16 @@
-#lang scheme/base
-(require (for-syntax scheme/base)
-         (for-syntax syntax/parse)
-         scheme/list
-         scheme/contract
-         "deriv.ss"
-         "deriv-util.ss"
-         "stx-util.ss"
-         "context.ss"
-         "steps.ss"
-         "reductions-config.ss")
-(provide (all-from-out "steps.ss")
-         (all-from-out "reductions-config.ss")
+#lang racket/base
+(require (for-syntax racket/base
+                     syntax/parse)
+         racket/list
+         racket/contract
+         "deriv.rkt"
+         "deriv-util.rkt"
+         "stx-util.rkt"
+         "context.rkt"
+         "steps.rkt"
+         "reductions-config.rkt")
+(provide (all-from-out "steps.rkt")
+         (all-from-out "reductions-config.rkt")
          DEBUG
          R
          !)
@@ -46,8 +46,6 @@
 ;;   [#:let var expr]
 ;;   [#:left-foot]
 ;;   [#:walk term2 description]
-;;   [#:walk/ctx pattern term2 description]
-;;   [#:walk/foci term2 foci1 foci2 description]
 ;;   [#:rename pattern rename [description]]
 ;;   [#:rename/no-step pattern stx stx]
 ;;   [#:reductions expr]
diff --git a/collects/macro-debugger/model/reductions.rkt b/collects/macro-debugger/model/reductions.rkt
index 574a211..ba5503f 100644
--- a/collects/macro-debugger/model/reductions.rkt
+++ b/collects/macro-debugger/model/reductions.rkt
@@ -1,10 +1,9 @@
-
-#lang scheme/base
-(require scheme/match
-         "stx-util.ss"
-         "deriv-util.ss"
-         "deriv.ss"
-         "reductions-engine.ss")
+#lang racket/base
+(require racket/match
+         "stx-util.rkt"
+         "deriv-util.rkt"
+         "deriv.rkt"
+         "reductions-engine.rkt")
 
 (provide reductions
          reductions+)
@@ -419,7 +418,15 @@
      ;; FIXME: add action
      (R [#:do (take-lift!)]
         [#:binders ids]
-        [#:reductions (list (walk expr ids 'local-lift))])]
+        [#:reductions
+         (list
+          (walk/talk 'local-lift
+                     (list "The macro lifted an expression"
+                           ""
+                           "Expression:"
+                           expr
+                           "Identifiers:"
+                           (datum->syntax #f ids))))])]
 
     [(struct local-lift-end (decl))
      ;; (walk/mono decl 'module-lift)
@@ -436,7 +443,9 @@
      [R [! ?1]
         ;; FIXME: use renames
         [#:binders names]
-        [#:when bindrhs => (BindSyntaxes bindrhs)]]]))
+        [#:when bindrhs => (BindSyntaxes bindrhs)]]]
+    [(struct local-remark (contents))
+     (R [#:reductions (list (walk/talk 'remark contents))])]))
 
 ;; List : ListDerivation -> RST
 (define (List ld)
@@ -453,32 +462,15 @@
   (match/count bd
     [(Wrap bderiv (es1 es2 pass1 trans pass2))
      (R [#:pattern ?block]
-        [#:parameterize ((block-syntax-bindings null)
-                         (block-value-bindings null)
-                         (block-expressions null))
-          [#:pass1]
-          [BlockPass ?block pass1]
-          [#:pass2]
-          [#:when (eq? trans 'letrec)
-                  [#:walk
-                   (let* ([pass2-stxs (wlderiv-es1 pass2)]
-                          [letrec-form (car pass2-stxs)]
-                          [letrec-kw (stx-car letrec-form)]
-                          [stx-bindings (reverse (block-syntax-bindings))]
-                          [val-bindings (reverse (block-value-bindings))]
-                          [exprs (block-expressions)]
-                          [mk-letrec-form (lambda (x) (datum->syntax #f x))])
-                     (list
-                      (mk-letrec-form
-                       `(,letrec-kw ,@(if (pair? stx-bindings)
-                                          (list stx-bindings)
-                                          null)
-                                    ,val-bindings
-                                    . ,exprs))))
-                   'block->letrec]]
-          [#:rename ?block (wlderiv-es1 pass2)]
-          [#:set-syntax (wlderiv-es1 pass2)]
-          [List ?block pass2]])]
+        [#:pass1]
+        [BlockPass ?block pass1]
+        [#:pass2]
+        [#:if (eq? trans 'letrec)
+              (;; FIXME: foci (difficult because of renaming?)
+               [#:walk (wlderiv-es1 pass2) 'block->letrec])
+              ([#:rename ?block (wlderiv-es1 pass2)]
+               [#:set-syntax (wlderiv-es1 pass2)])]
+        [List ?block pass2])]
     [#f
      (R)]))
 
@@ -515,13 +507,11 @@
         [#:pass1]
         [Expr ?first head]
         [! ?1]
-        [#:pass2]
         [#:pattern ((?define-values ?vars . ?body) . ?rest)]
         [#:rename (?vars . ?body) rename]
         [#:binders #'?vars]
         [! ?2]
-        [#:do (block-value-bindings
-               (cons (cons #'?vars #'?body) (block-value-bindings)))]
+        [#:pass2]
         [#:pattern (?first . ?rest)]
         [BlockPass ?rest rest])]
     [(cons (Wrap b:defstx (renames head ?1 rename ?2 bindrhs)) rest)
@@ -530,13 +520,11 @@
         [#:pass1]
         [Expr ?first head]
         [! ?1]
-        [#:pass2]
         [#:pattern ((?define-syntaxes ?vars . ?body) . ?rest)]
         [#:rename (?vars . ?body) rename]
         [#:binders #'?vars]
         [! ?2]
-        [#:do (block-syntax-bindings
-               (cons (cons #'?vars #'?body) (block-syntax-bindings)))]
+        [#:pass2]
         [#:pattern ((?define-syntaxes ?vars ?rhs) . ?rest)]
         [BindSyntaxes ?rhs bindrhs]
         [#:pattern (?first . ?rest)]
@@ -545,8 +533,6 @@
      (R [#:pattern (?first . ?rest)]
         [#:rename/no-step ?first (car renames) (cdr renames)]
         [Expr ?first head]
-        [#:do (block-expressions #'(?first . ?rest))]
-        ;; rest better be empty
         [BlockPass ?rest rest])]
     ))
 
diff --git a/collects/macro-debugger/model/steps.rkt b/collects/macro-debugger/model/steps.rkt
index b75d7b4..bb4feed 100644
--- a/collects/macro-debugger/model/steps.rkt
+++ b/collects/macro-debugger/model/steps.rkt
@@ -1,10 +1,10 @@
-
-#lang scheme/base
-(require "deriv.ss"
-         "deriv-util.ss")
+#lang racket/base
+(require "deriv.rkt"
+         "deriv-util.rkt")
 (provide (struct-out protostep)
          (struct-out step)
          (struct-out misstep)
+         (struct-out remarkstep)
          (struct-out state)
          (struct-out bigframe)
          context-fill
@@ -22,9 +22,11 @@
 ;; A Step is one of
 ;;  - (make-step StepType State State)
 ;;  - (make-misstep StepType State exn)
+;;  - (make-remarkstep StepType State (listof (U string syntax 'arrow)))
 (define-struct protostep (type s1) #:transparent)
 (define-struct (step protostep) (s2) #:transparent)
 (define-struct (misstep protostep) (exn) #:transparent)
+(define-struct (remarkstep protostep) (contents) #:transparent)
 
 ;; A State is
 ;;  (make-state stx stxs Context BigContext (listof id) (listof id) (listof stx) nat/#f)
@@ -89,6 +91,8 @@
     (splice-lifts     . "Splice definitions from lifted expressions")
     (splice-module-lifts . "Splice lifted module declarations")
 
+    (remark           . "Macro made a remark")
+
     (error            . "Error")))
 
 (define (step-type->string x)
diff --git a/collects/macro-debugger/model/stx-util.rkt b/collects/macro-debugger/model/stx-util.rkt
index 1073298..def760a 100644
--- a/collects/macro-debugger/model/stx-util.rkt
+++ b/collects/macro-debugger/model/stx-util.rkt
@@ -1,6 +1,5 @@
-
-#lang scheme/base
-(require (for-syntax scheme/base)
+#lang racket/base
+(require (for-syntax racket/base)
          syntax/stx)
 
 (provide (all-defined-out)
diff --git a/collects/macro-debugger/model/trace-raw.rkt b/collects/macro-debugger/model/trace-raw.rkt
index 5fc8702..40615d6 100644
--- a/collects/macro-debugger/model/trace-raw.rkt
+++ b/collects/macro-debugger/model/trace-raw.rkt
@@ -1,10 +1,9 @@
-
-#lang scheme/base
-(require scheme/class
+#lang racket/base
+(require racket/class
          parser-tools/lex
-         "deriv-tokens.ss"
-         "deriv-parser.ss"
-         "../syntax-browser.ss")
+         "deriv-tokens.rkt"
+         "deriv-parser.rkt"
+         "../syntax-browser.rkt")
 (provide (all-defined-out))
 
 (define current-expand-observe
diff --git a/collects/macro-debugger/model/trace.rkt b/collects/macro-debugger/model/trace.rkt
index 12e08c5..5f509e5 100644
--- a/collects/macro-debugger/model/trace.rkt
+++ b/collects/macro-debugger/model/trace.rkt
@@ -1,10 +1,9 @@
-
-#lang scheme/base
-(require scheme/promise
+#lang racket/base
+(require racket/promise
          parser-tools/lex
-         "deriv.ss"
-         "deriv-parser.ss"
-         "deriv-tokens.ss")
+         "deriv.rkt"
+         "deriv-parser.rkt"
+         "deriv-tokens.rkt")
 
 (provide trace
          trace*
diff --git a/collects/macro-debugger/model/yacc-ext.rkt b/collects/macro-debugger/model/yacc-ext.rkt
index 85ef44b..a8d262a 100644
--- a/collects/macro-debugger/model/yacc-ext.rkt
+++ b/collects/macro-debugger/model/yacc-ext.rkt
@@ -1,7 +1,6 @@
-
-#lang scheme/base
-(require (prefix-in yacc: parser-tools/yacc)
-         (for-syntax scheme/base))
+#lang racket/base
+(require (for-syntax racket/base)
+         (prefix-in yacc: parser-tools/yacc))
 (provide parser
          options
          productions
diff --git a/collects/macro-debugger/model/yacc-interrupted.rkt b/collects/macro-debugger/model/yacc-interrupted.rkt
index 7d7c491..9e8d2a5 100644
--- a/collects/macro-debugger/model/yacc-interrupted.rkt
+++ b/collects/macro-debugger/model/yacc-interrupted.rkt
@@ -1,9 +1,7 @@
-
-#lang scheme/base
-(require (for-syntax scheme/base
-                     mzlib/etc
+#lang racket/base
+(require (for-syntax racket/base
                      unstable/syntax)
-         "yacc-ext.ss")
+         "yacc-ext.rkt")
 (provide ! ? !!
          define-production-splitter
          skipped-token-values
diff --git a/collects/macro-debugger/stepper-text.rkt b/collects/macro-debugger/stepper-text.rkt
index 327b52a..15df8ef 100644
--- a/collects/macro-debugger/stepper-text.rkt
+++ b/collects/macro-debugger/stepper-text.rkt
@@ -1,13 +1,12 @@
-
-#lang scheme/base
-(require scheme/list
-         scheme/pretty
-         "model/trace.ss"
-         "model/reductions.ss"
-         "model/reductions-config.ss"
-         "model/steps.ss"
-         "syntax-browser/partition.ss"
-         "syntax-browser/pretty-helper.ss")
+#lang racket/base
+(require racket/list
+         racket/pretty
+         "model/trace.rkt"
+         "model/reductions.rkt"
+         "model/reductions-config.rkt"
+         "model/steps.rkt"
+         "syntax-browser/partition.rkt"
+         "syntax-browser/pretty-helper.rkt")
 (provide expand/step-text
          stepper-text)
 
diff --git a/collects/macro-debugger/stepper.rkt b/collects/macro-debugger/stepper.rkt
index 30fec39..07e782b 100644
--- a/collects/macro-debugger/stepper.rkt
+++ b/collects/macro-debugger/stepper.rkt
@@ -1,6 +1,5 @@
-
-#lang scheme/base
-(require "view/view.ss")
+#lang racket/base
+(require "view/view.rkt")
 (provide expand/step)
 
 (define (expand/step stx)
diff --git a/collects/macro-debugger/syntax-browser.rkt b/collects/macro-debugger/syntax-browser.rkt
index ce23cef..155ef03 100644
--- a/collects/macro-debugger/syntax-browser.rkt
+++ b/collects/macro-debugger/syntax-browser.rkt
@@ -1,6 +1,5 @@
-
-#lang scheme/base
-(require "syntax-browser/frame.ss")
+#lang racket/base
+(require "syntax-browser/frame.rkt")
 (provide browse-syntax
          browse-syntaxes
          make-syntax-browser)
diff --git a/collects/macro-debugger/syntax-browser/controller.rkt b/collects/macro-debugger/syntax-browser/controller.rkt
index 897a9c8..c5facda 100644
--- a/collects/macro-debugger/syntax-browser/controller.rkt
+++ b/collects/macro-debugger/syntax-browser/controller.rkt
@@ -1,10 +1,8 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:]
-                    [init-field/i init-field:])
-         "interfaces.ss"
-         "partition.ss"
+#lang racket/base
+(require racket/class
+         unstable/class-iop
+         "interfaces.rkt"
+         "partition.rkt"
          unstable/gui/notify)
 (provide controller%)
 
@@ -33,13 +31,13 @@
     (super-new)
     (listen-selected-syntax
      (lambda (new-value)
-       (for-each (lambda (display) (send: display display<%> refresh))
+       (for-each (lambda (display) (send/i display display<%> refresh))
                  displays)))))
 
 ;; mark-manager-mixin
 (define mark-manager-mixin
   (mixin () (mark-manager<%>)
-    (init-field: [primary-partition partition<%> (new-bound-partition)])
+    (init-field/i [primary-partition partition<%> (new-bound-partition)])
     (super-new)
 
     ;; get-primary-partition : -> partition
@@ -50,26 +48,20 @@
     (define/public-final (reset-primary-partition)
       (set! primary-partition (new-bound-partition)))))
 
-;; secondary-partition-mixin
-(define secondary-partition-mixin
-  (mixin (displays-manager<%>) (secondary-partition<%>)
+;; secondary-relation-mixin
+(define secondary-relation-mixin
+  (mixin (displays-manager<%>) (secondary-relation<%>)
     (inherit-field displays)
     (define-notify identifier=? (new notify-box% (value #f)))
-    (define-notify secondary-partition (new notify-box% (value #f)))
 
     (listen-identifier=?
      (lambda (name+proc)
-       (set-secondary-partition
-        (and name+proc
-             (new partition% (relation (cdr name+proc)))))))
-    (listen-secondary-partition
-     (lambda (p)
-       (for ([d displays])
-         (send: d display<%> refresh))))
+       (for ([d (in-list displays)])
+         (send/i d display<%> refresh))))
     (super-new)))
 
 (define controller%
-  (class* (secondary-partition-mixin
+  (class* (secondary-relation-mixin
            (selection-manager-mixin
             (mark-manager-mixin
              (displays-manager-mixin
diff --git a/collects/macro-debugger/syntax-browser/display.rkt b/collects/macro-debugger/syntax-browser/display.rkt
index b79f081..bc3b1ff 100644
--- a/collects/macro-debugger/syntax-browser/display.rkt
+++ b/collects/macro-debugger/syntax-browser/display.rkt
@@ -1,14 +1,14 @@
-#lang scheme/base
-(require scheme/class
-         scheme/gui
-         scheme/list
-         (rename-in unstable/class-iop
-                    [send/i send:]
-                    [init-field/i init-field:])
-         (only-in mzlib/etc begin-with-definitions)
-         "pretty-printer.ss"
-         "interfaces.ss"
-         "util.ss")
+#lang racket/base
+(require racket/class
+         racket/gui
+         racket/list
+         racket/block
+         framework
+         unstable/class-iop
+         "pretty-printer.rkt"
+         "interfaces.rkt"
+         "prefs.rkt"
+         "util.rkt")
 (provide print-syntax-to-editor
          code-style)
 
@@ -25,13 +25,13 @@
 ;;                       -> display<%>
 (define (print-syntax-to-editor stx text controller config columns
                                 [insertion-point (send text last-position)])
-  (begin-with-definitions
+  (block
    (define output-port (open-output-string/count-lines))
    (define range
      (pretty-print-syntax stx output-port 
-                          (send: controller controller<%> get-primary-partition)
-                          (length (send: config config<%> get-colors))
-                          (send: config config<%> get-suffix-option)
+                          (send/i controller controller<%> get-primary-partition)
+                          (length (send/i config config<%> get-colors))
+                          (send/i config config<%> get-suffix-option)
                           (send config get-pretty-styles)
                           columns))
    (define output-string (get-output-string output-port))
@@ -54,15 +54,15 @@
 ;; display%
 (define display%
   (class* object% (display<%>)
-    (init-field: [controller controller<%>]
-                 [config config<%>]
-                 [range range<%>])
+    (init-field/i [controller controller<%>]
+                  [config config<%>]
+                  [range range<%>])
     (init-field text
                 start-position
                 end-position)
 
     (define base-style
-      (code-style text (send: config config<%> get-syntax-font-size)))
+      (code-style text (send/i config config<%> get-syntax-font-size)))
 
     (define extra-styles (make-hasheq))
 
@@ -76,10 +76,10 @@
     ;; add-clickbacks : -> void
     (define/private (add-clickbacks)
       (define (the-clickback editor start end)
-        (send: controller selection-manager<%> set-selected-syntax
+        (send/i controller selection-manager<%> set-selected-syntax
                (clickback->stx
                 (- start start-position) (- end start-position))))
-      (for ([range (send: range range<%> all-ranges)])
+      (for ([range (send/i range range<%> all-ranges)])
         (let ([stx (range-obj range)]
               [start (range-start range)]
               [end (range-end range)])
@@ -89,7 +89,7 @@
     ;; clickback->stx : num num -> syntax
     ;; FIXME: use vectors for treerange-subs and do binary search to narrow?
     (define/private (clickback->stx start end)
-      (let ([treeranges (send: range range<%> get-treeranges)])
+      (let ([treeranges (send/i range range<%> get-treeranges)])
         (let loop* ([treeranges treeranges])
           (for/or ([tr treeranges])
             (cond [(and (= (treerange-start tr) start)
@@ -106,12 +106,12 @@
       (with-unlock text
         (send* text 
           (begin-edit-sequence #f)
-          (change-style unhighlight-d start-position end-position))
+          (change-style (unhighlight-d) start-position end-position))
         (apply-extra-styles)
         (let ([selected-syntax
-               (send: controller selection-manager<%>
+               (send/i controller selection-manager<%>
                       get-selected-syntax)])
-          (apply-secondary-partition-styles selected-syntax)
+          (apply-secondary-relation-styles selected-syntax)
           (apply-selection-styles selected-syntax))
         (send* text
           (end-edit-sequence))))
@@ -157,13 +157,16 @@
           (send delta set-delta-foreground color)
           (send style-list find-or-create-style base-style delta)))
       (define color-styles
-        (list->vector (map color-style (send: config config<%> get-colors))))
-      (define overflow-style (color-style "darkgray"))
+        (list->vector
+         (map color-style
+              (map translate-color
+                   (send/i config config<%> get-colors)))))
+      (define overflow-style (color-style (translate-color "darkgray")))
       (define color-partition
-        (send: controller mark-manager<%> get-primary-partition))
+        (send/i controller mark-manager<%> get-primary-partition))
       (define offset start-position)
       ;; Optimization: don't call change-style when new style = old style
-      (let tr*loop ([trs (send: range range<%> get-treeranges)] [old-style #f])
+      (let tr*loop ([trs (send/i range range<%> get-treeranges)] [old-style #f])
         (for ([tr trs])
           (define stx (treerange-obj tr))
           (define start (treerange-start tr))
@@ -179,7 +182,7 @@
     ;; primary-style : syntax partition (vector-of style-delta%) style-delta%
     ;;               -> style-delta%
     (define/private (primary-style stx partition color-vector overflow)
-      (let ([n (send: partition partition<%> get-partition stx)])
+      (let ([n (send/i partition partition<%> get-partition stx)])
         (cond [(< n (vector-length color-vector))
                (vector-ref color-vector n)]
               [else
@@ -192,34 +195,34 @@
     ;; Applies externally-added styles (such as highlighting)
     (define/private (apply-extra-styles)
       (for ([(stx style-deltas) extra-styles])
-        (for ([r (send: range range<%> get-ranges stx)])
+        (for ([r (send/i range range<%> get-ranges stx)])
           (for ([style-delta style-deltas])
             (restyle-range r style-delta)))))
 
-    ;; apply-secondary-partition-styles : selected-syntax -> void
+    ;; apply-secondary-relation-styles : selected-syntax -> void
     ;; If the selected syntax is an identifier, then styles all identifiers
-    ;; in the same partition in blue.
-    (define/private (apply-secondary-partition-styles selected-syntax)
+    ;; in the relation with it.
+    (define/private (apply-secondary-relation-styles selected-syntax)
       (when (identifier? selected-syntax)
-        (let ([partition
-               (send: controller secondary-partition<%>
-                      get-secondary-partition)])
-          (when partition
-            (for ([id (send: range range<%> get-identifier-list)])
-              (when (send: partition partition<%>
-                           same-partition? selected-syntax id)
+        (let* ([name+relation
+                (send/i controller secondary-relation<%>
+                        get-identifier=?)]
+               [relation (and name+relation (cdr name+relation))])
+          (when relation
+            (for ([id (send/i range range<%> get-identifier-list)])
+              (when (relation selected-syntax id)
                 (draw-secondary-connection id)))))))
 
     ;; apply-selection-styles : syntax -> void
     ;; Styles subterms eq to the selected syntax
     (define/private (apply-selection-styles selected-syntax)
-      (for ([r (send: range range<%> get-ranges selected-syntax)])
-        (restyle-range r select-highlight-d)))
+      (for ([r (send/i range range<%> get-ranges selected-syntax)])
+        (restyle-range r (select-highlight-d))))
 
     ;; draw-secondary-connection : syntax -> void
     (define/private (draw-secondary-connection stx2)
-      (for ([r (send: range range<%> get-ranges stx2)])
-        (restyle-range r select-sub-highlight-d)))
+      (for ([r (send/i range range<%> get-ranges stx2)])
+        (restyle-range r (select-sub-highlight-d))))
 
     ;; restyle-range : (cons num num) style-delta% -> void
     (define/private (restyle-range r style)
@@ -233,11 +236,11 @@
 
     ;; Initialize
     (super-new)
-    (send: controller controller<%> add-syntax-display this)))
+    (send/i controller controller<%> add-syntax-display this)))
 
 ;; fixup-parentheses : string range -> void
 (define (fixup-parentheses string range)
-  (for ([r (send: range range<%> all-ranges)])
+  (for ([r (send/i range range<%> all-ranges)])
     (let ([stx (range-obj r)]
           [start (range-start r)]
           [end (range-end r)])
@@ -258,7 +261,7 @@
 ;; code-style : text<%> number/#f -> style<%>
 (define (code-style text font-size)
   (let* ([style-list (send text get-style-list)]
-         [style (send style-list find-named-style "Standard")])
+         [style (send style-list find-named-style (editor:get-default-color-style-name))])
     (if font-size
         (send style-list find-or-create-style
               style
@@ -272,13 +275,98 @@
       (make-object string-snip% ""))
     (super-instantiate ())))
 
+;; Color translation
+
+;; translate-color : color-string -> color%
+(define (translate-color color-string)
+  (let ([c (make-object color% color-string)])
+    (if (pref:invert-colors?)
+        (let-values ([(r* g* b*)
+                      (lightness-invert (send c red) (send c green) (send c blue))])
+          #|
+          (printf "translate: ~s -> ~s\n"
+                  (list (send c red) (send c green) (send c blue))
+                  (list r* g* b*))
+          |#
+          (make-object color% r* g* b*))
+        c)))
+
+;; lightness-invert : uint8 uint8 uint8 -> (values uint8 uint8 uint8)
+(define (lightness-invert r g b)
+  (define (c x)
+    (/ (exact->inexact x) 255.0))
+  (define (d x)
+    (inexact->exact (round (* x 255))))
+  (let-values ([(r g b) (lightness-invert* (c r) (c g) (c b))])
+    (values (d r) (d g) (d b))))
+
+(define (lightness-invert* R G B)
+  (let-values ([(Hp Sl L) (rgb->hsl* R G B)])
+    (hsl*->rgb Hp Sl (- 1.0 L))))
+
+(define (rgb->hsl* R G B)
+  (define M (max R G B))
+  (define m (min R G B))
+  (define C (- M m))
+  (define Hp
+    (cond [(zero? C)
+           ;; Undefined, but use 0
+           0.0]
+          [(= M R)
+           (realmod* (/ (- G B) C) 6)]
+          [(= M G)
+           (+ (/ (- B R) C) 2)]
+          [(= M B)
+           (+ (/ (- R G) C) 4)]))
+  (define L (* 0.5 (+ M m)))
+  (define Sl
+    (cond [(zero? C) 0.0]
+          [(>= L 0.5) (/ C (* 2 L))]
+          [else (/ C (- 2 (* 2 L)))]))
+  
+  (values Hp Sl L))
+
+(define (hsl*->rgb Hp Sl L)
+  (define C
+    (cond [(>= L 0.5) (* 2 L Sl)]
+          [else (* (- 2 (* 2 L)) Sl)]))
+  (define X (* C (- 1 (abs (- (realmod Hp 2) 1)))))
+  (define-values (R1 G1 B1)
+    (cond [(< Hp 1) (values C X 0)]
+          [(< Hp 2) (values X C 0)]
+          [(< Hp 3) (values 0 C X)]
+          [(< Hp 4) (values 0 X C)]
+          [(< Hp 5) (values X 0 C)]
+          [(< Hp 6) (values C 0 X)]))
+  (define m (- L (* 0.5 C)))
+  (values (+ R1 m) (+ G1 m) (+ B1 m)))
+
+;; realmod : real integer -> real
+;; Adjusts a real number to [0, base]
+(define (realmod x base)
+  (define xint (ceiling x))
+  (define m (modulo xint base))
+  (realmod* (- m (- xint x)) base))
+
+;; realmod* : real real -> real
+;; Adjusts a number in [-base, base] to [0,base]
+;; Not a real mod, but faintly reminiscent.
+(define (realmod* x base)
+  (if (negative? x)
+      (+ x base)
+      x))
+
 ;; Styles
 
-(define (highlight-style-delta color em?)
-  (let ([sd (new style-delta%)])
-    (unless em? (send sd set-delta-background color))
+(define (highlight-style-delta raw-color em?
+                               #:translate-color? [translate-color? #t])
+  (let* ([sd (new style-delta%)])
+    (unless em?
+      (send sd set-delta-background
+            (if translate-color? (translate-color raw-color) raw-color)))
     (when em? (send sd set-weight-on 'bold))
-    (unless em? (send sd set-underlined-off #t)
+    (unless em?
+      ;; (send sd set-underlined-off #t)
       (send sd set-weight-off 'bold))
     sd))
 
@@ -287,10 +375,17 @@
     (send sd set-underlined-on #t)
     sd))
 
-(define selection-color "yellow")
-(define subselection-color "yellow")
+(define (mk-2-constant-style bow-color em? [wob-color (translate-color bow-color)])
+  (let ([wob-version (highlight-style-delta wob-color em? #:translate-color? #f)]
+        [bow-version (highlight-style-delta bow-color em? #:translate-color? #f)])
+    (λ ()
+      (if (pref:invert-colors?)
+          wob-version
+          bow-version))))
 
-(define select-highlight-d (highlight-style-delta selection-color #t))
-(define select-sub-highlight-d (highlight-style-delta subselection-color #f))
+(define select-highlight-d
+  (mk-2-constant-style "yellow" #t "darkgoldenrod"))
+(define select-sub-highlight-d
+  (mk-2-constant-style "yellow" #f "darkgoldenrod"))
 
-(define unhighlight-d (highlight-style-delta "white" #f))
+(define unhighlight-d (mk-2-constant-style "white" #f #|"black"|#))
diff --git a/collects/macro-debugger/syntax-browser/embed.rkt b/collects/macro-debugger/syntax-browser/embed.rkt
index 2edc5e6..b3cb5d3 100644
--- a/collects/macro-debugger/syntax-browser/embed.rkt
+++ b/collects/macro-debugger/syntax-browser/embed.rkt
@@ -1,11 +1,10 @@
+#lang racket/base
+(require "interfaces.rkt"
+         "widget.rkt"
+         "keymap.rkt"
+         "partition.rkt")
 
-#lang scheme/base
-(require "interfaces.ss"
-         "widget.ss"
-         "keymap.ss"
-         "partition.ss")
-
-(provide (all-from-out "interfaces.ss")
-         (all-from-out "widget.ss")
-         (all-from-out "keymap.ss")
+(provide (all-from-out "interfaces.rkt")
+         (all-from-out "widget.rkt")
+         (all-from-out "keymap.rkt")
          identifier=-choices)
diff --git a/collects/macro-debugger/syntax-browser/frame.rkt b/collects/macro-debugger/syntax-browser/frame.rkt
index 7b4a3ff..d59f2eb 100644
--- a/collects/macro-debugger/syntax-browser/frame.rkt
+++ b/collects/macro-debugger/syntax-browser/frame.rkt
@@ -1,17 +1,13 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [define/i define:]
-                    [send/i send:]
-                    [send*/i send*:]
-                    [init-field/i init-field:])
-         scheme/gui
-         framework/framework
-         scheme/list
-         "interfaces.ss"
-         "partition.ss"
-         "prefs.ss"
-         "widget.ss")
+#lang racket/base
+(require racket/class
+         racket/gui
+         racket/list
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "partition.rkt"
+         "prefs.rkt"
+         "widget.rkt")
 (provide browse-syntax
          browse-syntaxes
          make-syntax-browser
@@ -26,7 +22,7 @@
 (define (browse-syntaxes stxs)
   (let ((w (make-syntax-browser)))
     (for ([stx stxs])
-      (send*: w syntax-browser<%>
+      (send*/i w syntax-browser<%>
         (add-syntax stx)
         (add-separator)))))
 
@@ -41,17 +37,17 @@
   (class* frame% ()
     (inherit get-width
              get-height)
-    (init-field: [config config<%> (new syntax-prefs%)])
+    (init-field/i [config config<%> (new syntax-prefs%)])
     (super-new (label "Syntax Browser")
-               (width (send: config config<%> get-width))
-               (height (send: config config<%> get-height)))
-    (define: widget syntax-browser<%>
+               (width (send/i config config<%> get-width))
+               (height (send/i config config<%> get-height)))
+    (define/i widget syntax-browser<%>
       (new syntax-widget/controls%
            (parent this)
            (config config)))
     (define/public (get-widget) widget)
     (define/augment (on-close)
-      (send*: config config<%>
+      (send*/i config config<%>
         (set-width (get-width))
         (set-height (get-height)))
       (send widget shutdown)
@@ -81,22 +77,22 @@
            (choices (map car -identifier=-choices))
            (callback 
             (lambda (c e)
-              (send: (get-controller) controller<%> set-identifier=?
+              (send/i (get-controller) controller<%> set-identifier=?
                      (assoc (send c get-string-selection)
                             -identifier=-choices))))))
     (new button% 
          (label "Clear")
          (parent -control-panel)
-         (callback (lambda _ (send: (get-controller) controller<%> set-selected-syntax #f))))
+         (callback (lambda _ (send/i (get-controller) controller<%> set-selected-syntax #f))))
     (new button%
          (label "Properties")
          (parent -control-panel)
          (callback
           (lambda _ 
-            (send: config config<%> set-props-shown? 
-                   (not (send: config config<%> get-props-shown?))))))
+            (send/i config config<%> set-props-shown? 
+                   (not (send/i config config<%> get-props-shown?))))))
 
-    (send: (get-controller) controller<%> listen-identifier=?
+    (send/i (get-controller) controller<%> listen-identifier=?
            (lambda (name+func)
              (send -choice set-selection
                    (or (send -choice find-string (car name+func)) 0))))
diff --git a/collects/macro-debugger/syntax-browser/hrule-snip.rkt b/collects/macro-debugger/syntax-browser/hrule-snip.rkt
index 148d3f2..c7bb859 100644
--- a/collects/macro-debugger/syntax-browser/hrule-snip.rkt
+++ b/collects/macro-debugger/syntax-browser/hrule-snip.rkt
@@ -1,8 +1,6 @@
-
-#lang scheme/base
-
-(require scheme/class
-         scheme/gui)
+#lang racket/base
+(require racket/class
+         racket/gui)
 (provide hrule-snip%)
 
 ;; hrule-snip%
@@ -53,5 +51,5 @@
 (define snip-class (new hrule-snipclass%))
 (send snip-class set-version 1)
 (send snip-class set-classname
-      (format "~s" '(lib "hrule-snip.ss" "macro-debugger" "syntax-browser")))
+      (format "~s" '(lib "hrule-snip.rkt" "macro-debugger" "syntax-browser")))
 (send (get-the-snip-class-list) add snip-class)
diff --git a/collects/macro-debugger/syntax-browser/image.rkt b/collects/macro-debugger/syntax-browser/image.rkt
index d8151c5..23fa15c 100644
--- a/collects/macro-debugger/syntax-browser/image.rkt
+++ b/collects/macro-debugger/syntax-browser/image.rkt
@@ -1,11 +1,11 @@
-#lang scheme/base
-(require scheme/contract
-         scheme/class
-         scheme/gui
+#lang racket/base
+(require racket/contract
+         racket/class
+         racket/gui
          framework
-         "prefs.ss"
-         "controller.ss"
-         "display.ss")
+         "prefs.rkt"
+         "controller.rkt"
+         "display.rkt")
 
 #|
 
@@ -36,7 +36,7 @@ TODO: tacked arrows
 ;; print-syntax-columns : (parameter-of (U number 'infinity))
 (define print-syntax-columns (make-parameter 40))
 
-(define standard-text% (editor:standard-style-list-mixin text%))
+(define standard-text% (text:foreground-color-mixin (editor:standard-style-list-mixin text:basic%)))
 
 ;; print-syntax-to-png : syntax path -> void
 (define (print-syntax-to-png stx file
@@ -54,7 +54,7 @@ TODO: tacked arrows
   (define dc (new bitmap-dc% (bitmap (make-object bitmap% 1 1))))
   (define char-width
     (let* ([sl (send t get-style-list)]
-           [style (send sl find-named-style "Standard")]
+           [style (send sl find-named-style (editor:get-default-color-style-name))]
            [font (send style get-font)])
       (send dc set-font font)
       (send dc get-char-width)))
@@ -89,7 +89,7 @@ TODO: tacked arrows
 (define (prepare-editor stx columns)
   (define t (new standard-text%))
   (define sl (send t get-style-list))
-  (send t change-style (send sl find-named-style "Standard"))
+  (send t change-style (send sl find-named-style (editor:get-default-color-style-name)))
   (print-syntax-to-editor stx t 
                           (new controller%) (new syntax-prefs/readonly%)
                           columns (send t last-position))
diff --git a/collects/macro-debugger/syntax-browser/interfaces.rkt b/collects/macro-debugger/syntax-browser/interfaces.rkt
index 411f922..9d04748 100644
--- a/collects/macro-debugger/syntax-browser/interfaces.rkt
+++ b/collects/macro-debugger/syntax-browser/interfaces.rkt
@@ -1,7 +1,7 @@
-#lang scheme/base
-(require scheme/class
+#lang racket/base
+(require racket/class
          unstable/class-iop
-         (for-syntax scheme/base))
+         (for-syntax racket/base))
 (provide (all-defined-out))
 
 ;; Helpers
@@ -14,7 +14,7 @@
           [else (error '->string)]))
   (string->symbol (apply string-append (map ->string args))))
 
-;; not in notify.ss because notify depends on scheme/gui
+;; not in notify.rkt because notify depends on gui
 (define-interface-expander methods:notify
   (lambda (stx)
     (syntax-case stx ()
@@ -61,18 +61,16 @@
    ;; reset-primary-partition : -> void
    reset-primary-partition))
 
-;; secondary-partition<%>
-(define-interface secondary-partition<%> ()
-  (;; secondary-partition : notify-box of partition<%>
-   ;; identifier=? : notify-box of (cons string procedure)
-   (methods:notify secondary-partition
-                   identifier=?)))
+;; secondary-relation<%>
+(define-interface secondary-relation<%> ()
+  (;; identifier=? : notify-box of (cons string (U #f (id id -> bool)))
+   (methods:notify identifier=?)))
 
 ;; controller<%>
 (define-interface controller<%> (displays-manager<%>
                                  selection-manager<%>
                                  mark-manager<%>
-                                 secondary-partition<%>)
+                                 secondary-relation<%>)
   ())
 
 
diff --git a/collects/macro-debugger/syntax-browser/keymap.rkt b/collects/macro-debugger/syntax-browser/keymap.rkt
index 7da1a99..afc3fc2 100644
--- a/collects/macro-debugger/syntax-browser/keymap.rkt
+++ b/collects/macro-debugger/syntax-browser/keymap.rkt
@@ -1,10 +1,10 @@
-#lang scheme/base
-(require scheme/class
-         scheme/gui
-         scheme/pretty
+#lang racket/base
+(require racket/class
+         racket/gui
+         racket/pretty
          unstable/gui/notify
-         "interfaces.ss"
-         "partition.ss")
+         "interfaces.rkt"
+         "partition.rkt")
 (provide syntax-keymap%)
 
 (define keymap/popup%
diff --git a/collects/macro-debugger/syntax-browser/partition.rkt b/collects/macro-debugger/syntax-browser/partition.rkt
index 54cb429..35f662d 100644
--- a/collects/macro-debugger/syntax-browser/partition.rkt
+++ b/collects/macro-debugger/syntax-browser/partition.rkt
@@ -1,157 +1,45 @@
-
-#lang scheme/base
-(require scheme/class
-         syntax/boundmap
+#lang racket/base
+(require racket/class
          syntax/stx
-         "interfaces.ss")
+         "interfaces.rkt"
+         "../util/stxobj.rkt")
 (provide new-bound-partition
-         partition%
          identifier=-choices)
 
 (define (new-bound-partition)
   (new bound-partition%))
 
-;; representative-symbol : symbol
-;; Must be fresh---otherwise, using it could detect rename wraps 
-;; instead of only marks.
-;; For example, in (lambda (representative) representative)
-(define representative-symbol
-  (gensym 'representative))
-
-;; unmarked-syntax : identifier
-;; Has no marks---used to initialize bound partition so that 
-;; unmarked syntax always gets colored "black"
-(define unmarked-syntax
-  (datum->syntax #f representative-symbol))
-
-(define partition%
-  (class* object% (partition<%>)
-    (init relation)
-
-    (define related? (or relation (lambda (a b) #f)))
-    (field (rep=>num (make-hasheq)))
-    (field (obj=>rep (make-weak-hasheq)))
-    (field (reps null))
-    (field (next-num 0))
-    
-    (define/public (get-partition obj)
-      (rep->partition (obj->rep obj)))
-
-    (define/public (same-partition? A B)
-      (= (get-partition A) (get-partition B)))
-    
-    (define/private (obj->rep obj)
-      (hash-ref obj=>rep obj (lambda () (obj->rep* obj))))
-    
-    (define/public (count)
-      next-num)
-
-    (define/private (obj->rep* obj)
-      (let loop ([reps reps])
-        (cond [(null? reps)
-               (new-rep obj)]
-              [(related? obj (car reps))
-               (hash-set! obj=>rep obj (car reps))
-               (car reps)]
-              [else
-               (loop (cdr reps))])))
-
-    (define/private (new-rep rep)
-      (hash-set! rep=>num rep next-num)
-      (set! next-num (add1 next-num))
-      (set! reps (cons rep reps))
-      rep)
-    
-    (define/private (rep->partition rep)
-      (hash-ref rep=>num rep))
-
-    ;; Nearly useless as it stands
-    (define/public (dump)
-      (hash-for-each 
-       rep=>num
-       (lambda (k v)
-         (printf "~s => ~s~n" k v))))
-
-    (get-partition unmarked-syntax)
-    (super-new)
-    ))
-
 ;; bound-partition%
 (define bound-partition%
   (class* object% (partition<%>)
-    ;; numbers : bound-identifier-mapping[identifier => number]
-    (define numbers (make-bound-identifier-mapping))
+
+    ;; simplified : hash[(listof nat) => nat]
+    (define simplified (make-hash))
+
+    ;; next-number : nat
     (define next-number 0)
-    
+
     (define/public (get-partition stx)
-      (let* ([r (representative stx)]
-             [n (bound-identifier-mapping-get numbers r (lambda _ #f))])
-        (or n
-            (begin0 next-number
-              (bound-identifier-mapping-put! numbers r next-number)
-              #;(printf "primary partition new stx:~n~s~n~s~n" stx (syntax->datum stx))
-              (set! next-number (add1 next-number))))))
-    
+      (let ([marks (simplify-marks (get-marks stx))])
+        (or (hash-ref simplified marks #f)
+            (let ([n next-number])
+              (hash-set! simplified marks n)
+              (set! next-number (add1 n))
+              n))))
+
     (define/public (same-partition? a b)
       (= (get-partition a) (get-partition b)))
-    
+
     (define/public (count)
       next-number)
-    
-    (define/private (representative stx)
-      (datum->syntax stx representative-symbol))
 
-    (get-partition unmarked-syntax)
+    (get-partition (datum->syntax #f 'nowhere))
     (super-new)))
 
-;; Different identifier relations for highlighting.
-
-(define (lift/rep id=?)
-  (lambda (A B)
-    (let ([ra (datum->syntax A representative-symbol)]
-          [rb (datum->syntax B representative-symbol)])
-      (id=? ra rb))))
-
-(define (lift id=?)
-  (lambda (A B)
-    (and (identifier? A) (identifier? B) (id=? A B))))
-
-;; id:same-marks? : syntax syntax -> boolean
-(define id:same-marks?
-  (lift/rep bound-identifier=?))
-
-;; id:X-module=? : identifier identifier -> boolean
-;; If both module-imported, do they come from the same module?
-;; If both top-bound, then same source.
-(define (id:source-module=? a b)
-  (let ([ba (identifier-binding a)]
-        [bb (identifier-binding b)])
-    (cond [(or (eq? 'lexical ba) (eq? 'lexical bb))
-           (free-identifier=? a b)]
-          [(and (not ba) (not bb))
-           #t]
-          [(or (not ba) (not bb))
-           #f]
-          [else
-           (eq? (car ba) (car bb))])))
-(define (id:nominal-module=? A B)
-  (let ([ba (identifier-binding A)]
-        [bb (identifier-binding B)])
-    (cond [(or (eq? 'lexical ba) (eq? 'lexical bb))
-           (free-identifier=? A B)]
-          [(or (not ba) (not bb))
-           (and (not ba) (not bb))]
-          [else (eq? (caddr ba) (caddr bb))])))
-
-(define (symbolic-identifier=? A B)
-  (eq? (syntax-e A) (syntax-e B)))
+;; ==== Identifier relations ====
 
 (define identifier=-choices
   (make-parameter
    `(("<nothing>" . #f)
      ("bound-identifier=?"  . ,bound-identifier=?)
-     ("free-identifier=?" . ,free-identifier=?)
-     ("module-or-top-identifier=?" . ,module-or-top-identifier=?)
-     ("symbolic-identifier=?" . ,symbolic-identifier=?)
-     ("same source module" . ,id:source-module=?)
-     ("same nominal module" . ,id:nominal-module=?))))
+     ("free-identifier=?" . ,free-identifier=?))))
diff --git a/collects/macro-debugger/syntax-browser/prefs.rkt b/collects/macro-debugger/syntax-browser/prefs.rkt
index 8df1e63..ec9c0ad 100644
--- a/collects/macro-debugger/syntax-browser/prefs.rkt
+++ b/collects/macro-debugger/syntax-browser/prefs.rkt
@@ -1,13 +1,15 @@
-#lang scheme/base
-(require scheme/class
-         framework/framework
-         "interfaces.ss"
+#lang racket/base
+(require racket/class
+         framework
+         "interfaces.rkt"
          unstable/gui/notify
          unstable/gui/prefs)
 (provide prefs-base%
          syntax-prefs-base%
          syntax-prefs%
-         syntax-prefs/readonly%)
+         syntax-prefs/readonly%
+
+         pref:invert-colors?)
 
 (preferences:set-default 'SyntaxBrowser:Width 700 number?)
 (preferences:set-default 'SyntaxBrowser:Height 600 number?)
@@ -19,6 +21,8 @@
 (define pref:props-percentage (pref:get/set 'SyntaxBrowser:PropertiesPanelPercentage))
 (define pref:props-shown? (pref:get/set 'SyntaxBrowser:PropertiesPanelShown))
 
+(define pref:invert-colors? (pref:get/set 'framework:white-on-black?))
+
 (define prefs-base%
   (class object%
     ;; suffix-option : SuffixOption
diff --git a/collects/macro-debugger/syntax-browser/pretty-helper.rkt b/collects/macro-debugger/syntax-browser/pretty-helper.rkt
index af67d15..1f58acf 100644
--- a/collects/macro-debugger/syntax-browser/pretty-helper.rkt
+++ b/collects/macro-debugger/syntax-browser/pretty-helper.rkt
@@ -1,11 +1,10 @@
-#lang scheme/base
-(require scheme/class
-         scheme/pretty
-         (rename-in unstable/class-iop
-                    [send/i send:])
+#lang racket/base
+(require racket/class
+         racket/pretty
+         unstable/class-iop
          syntax/stx
          unstable/struct
-         "interfaces.ss")
+         "interfaces.rkt")
 (provide (all-defined-out))
 
 ;; Problem: If stx1 and stx2 are two distinguishable syntax objects, it
@@ -32,7 +31,7 @@
      [print-vector-length #f]
      [print-hash-table #t]
      [print-honu #f])
-    (pretty-print datum port)))
+    (pretty-write datum port)))
 
 (define-struct syntax-dummy (val))
 (define-struct (id-syntax-dummy syntax-dummy) (remap))
@@ -64,12 +63,12 @@
       ((never)
        (make-id-syntax-dummy sym sym))
       ((always)
-       (let ([n (send: partition partition<%> get-partition id)])
+       (let ([n (send/i partition partition<%> get-partition id)])
          (if (zero? n)
              (make-id-syntax-dummy sym sym)
              (make-id-syntax-dummy (suffix sym n) sym))))
       ((over-limit)
-       (let ([n (send: partition partition<%> get-partition id)])
+       (let ([n (send/i partition partition<%> get-partition id)])
          (if (<= n limit)
              (make-id-syntax-dummy sym sym)
              (make-id-syntax-dummy (suffix sym n) sym))))))
@@ -82,7 +81,7 @@
                => (lambda (datum) datum)]
               [(and partition (identifier? obj))
                (when (and (eq? suffixopt 'all-if-over-limit)
-                          (> (send: partition partition<%> count) limit))
+                          (> (send/i partition partition<%> count) limit))
                  (call-with-values (lambda () (table stx partition #f 'always))
                                    escape))
                (let ([lp-datum (make-identifier-proxy obj)])
@@ -91,7 +90,7 @@
                  lp-datum)]
               [(and (syntax? obj) (check+convert-special-expression obj))
                => (lambda (newobj)
-                    (when partition (send: partition partition<%> get-partition obj))
+                    (when partition (send/i partition partition<%> get-partition obj))
                     (let* ([inner (cadr newobj)]
                            [lp-inner-datum (loop inner)]
                            [lp-datum (list (car newobj) lp-inner-datum)])
@@ -101,7 +100,7 @@
                       (hash-set! stx=>flat obj lp-datum)
                       lp-datum))]
               [(syntax? obj)
-               (when partition (send: partition partition<%> get-partition obj))
+               (when partition (send/i partition partition<%> get-partition obj))
                (let ([lp-datum (loop (syntax-e obj))])
                  (hash-set! flat=>stx lp-datum obj)
                  (hash-set! stx=>flat obj lp-datum)
diff --git a/collects/macro-debugger/syntax-browser/pretty-printer.rkt b/collects/macro-debugger/syntax-browser/pretty-printer.rkt
index 4787e83..442115c 100644
--- a/collects/macro-debugger/syntax-browser/pretty-printer.rkt
+++ b/collects/macro-debugger/syntax-browser/pretty-printer.rkt
@@ -1,10 +1,10 @@
-#lang scheme/base
-(require scheme/list
-         scheme/class
-         scheme/pretty
-         scheme/gui
-         "pretty-helper.ss"
-         "interfaces.ss")
+#lang racket/base
+(require racket/list
+         racket/class
+         racket/pretty
+         racket/gui
+         "pretty-helper.rkt"
+         "interfaces.rkt")
 (provide pretty-print-syntax)
 
 ;; FIXME: Need to disable printing of structs with custom-write property
diff --git a/collects/macro-debugger/syntax-browser/properties.rkt b/collects/macro-debugger/syntax-browser/properties.rkt
index f6a1a9d..2d0a482 100644
--- a/collects/macro-debugger/syntax-browser/properties.rkt
+++ b/collects/macro-debugger/syntax-browser/properties.rkt
@@ -1,14 +1,32 @@
-#lang scheme/base
-(require scheme/class
-         scheme/gui
-         (rename-in unstable/class-iop
-                    [send/i send:])
-         "interfaces.ss"
-         "util.ss"
-         "../util/mpi.ss")
+#lang racket/base
+(require racket/class
+         racket/gui
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "util.rkt"
+         "../util/mpi.rkt"
+         "../util/stxobj.rkt")
 (provide properties-view%
          properties-snip%)
 
+(define color-text-default-style-name
+  "macro-debugger/syntax-browser/properties color-text% basic")
+
+(define color-text%
+  (class (editor:standard-style-list-mixin text:basic%)
+    (inherit get-style-list)
+    (define/override (default-style-name)
+      color-text-default-style-name)
+    (super-new)
+    (let* ([sl (get-style-list)]
+           [standard
+            (send sl find-named-style (editor:get-default-color-style-name))]
+           [basic
+            (send sl find-or-create-style standard
+                  (make-object style-delta% 'change-family 'default))])
+      (send sl new-named-style color-text-default-style-name basic))))
+
 ;; properties-view-base-mixin
 (define properties-view-base-mixin
   (mixin () ()
@@ -22,13 +40,13 @@
     (define mode 'term)
 
     ;; text : text%
-    (field (text (new text%)))
+    (field (text (new color-text%)))
     (field (pdisplayer (new properties-displayer% (text text))))
 
-    (send: controller selection-manager<%> listen-selected-syntax
-           (lambda (stx)
-             (set! selected-syntax stx)
-             (refresh)))
+    (send/i controller selection-manager<%> listen-selected-syntax
+            (lambda (stx)
+              (set! selected-syntax stx)
+              (refresh)))
     (super-new)
 
     ;; get-mode : -> symbol
@@ -122,7 +140,7 @@
            (callback
             (lambda (tp e)
               (set-mode (cdr (list-ref tab-choices (send tp get-selection))))))))
-    (define ecanvas (new editor-canvas% (editor text) (parent tab-panel)))))
+    (define ecanvas (new canvas:color% (editor text) (parent tab-panel)))))
 
 ;; properties-displayer%
 (define properties-displayer%
@@ -188,7 +206,8 @@
     (define/public (display-stxobj-info stx)
       (display-source-info stx)
       (display-extra-source-info stx)
-      (display-symbol-property-info stx))
+      (display-symbol-property-info stx)
+      (display-marks stx))
 
     ;; display-source-info : syntax -> void
     (define/private (display-source-info stx)
@@ -226,7 +245,13 @@
           (display "No additional properties available.\n" n/a-sd))
         (when (pair? keys)
           (for-each (lambda (k) (display-subkv/value k (syntax-property stx k)))
-                    keys))))
+                    keys))
+        (display "\n" #f)))
+
+    ;; display-marks : syntax -> void
+    (define/private (display-marks stx)
+      (display "Marks: " key-sd)
+      (display (format "~s\n" (simplify-marks (get-marks stx))) #f))
 
     ;; display-kv : any any -> void
     (define/private (display-kv key value)
diff --git a/collects/macro-debugger/syntax-browser/snip-decorated.rkt b/collects/macro-debugger/syntax-browser/snip-decorated.rkt
index 55f0574..c408255 100644
--- a/collects/macro-debugger/syntax-browser/snip-decorated.rkt
+++ b/collects/macro-debugger/syntax-browser/snip-decorated.rkt
@@ -1,14 +1,13 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:])
-         mzlib/string
-         mred
-         "interfaces.ss"
-         "controller.ss"
-         "properties.ss"
-         "prefs.ss"
-         (except-in "snip.ss"
+#lang racket/base
+(require racket/class
+         racket/gui
+         (only-in mzlib/string read-from-string)
+         unstable/class-iop
+         "interfaces.rkt"
+         "controller.rkt"
+         "properties.rkt"
+         "prefs.rkt"
+         (except-in "snip.rkt"
                     snip-class))
 
 (provide decorated-syntax-snip%
@@ -145,8 +144,8 @@
     (define/public (read-special src line col pos)
       (send the-syntax-snip read-special src line col pos))
 
-    (send: config config<%> listen-props-shown?
-           (lambda (?) (refresh-contents)))
+    (send/i config config<%> listen-props-shown?
+            (lambda (?) (refresh-contents)))
 
     (super-new)
     (set-snipclass snip-class)
@@ -198,7 +197,7 @@
 
 ;; SNIPCLASS
 
-;; COPIED AND MODIFIED from mrlib/syntax-browser.ss
+;; COPIED AND MODIFIED from mrlib/syntax-browser.rkt
 (define decorated-syntax-snipclass%
   (class snip-class%
     (define/override (read stream)
@@ -210,4 +209,4 @@
 (define snip-class (make-object decorated-syntax-snipclass%))
 (send snip-class set-version 2)
 (send snip-class set-classname
-      (format "~s" '(lib "macro-debugger/syntax-browser/snip-decorated.ss")))
+      (format "~s" '(lib "macro-debugger/syntax-browser/snip-decorated.rkt")))
diff --git a/collects/macro-debugger/syntax-browser/snip.rkt b/collects/macro-debugger/syntax-browser/snip.rkt
index 7116afc..545b213 100644
--- a/collects/macro-debugger/syntax-browser/snip.rkt
+++ b/collects/macro-debugger/syntax-browser/snip.rkt
@@ -1,16 +1,14 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:])
-         scheme/match
-         mzlib/string
-         mred
+#lang racket/base
+(require racket/class
+         racket/gui
+         racket/match
+         (only-in mzlib/string read-from-string)
          framework
-         "interfaces.ss"
-         "display.ss"
-         "controller.ss"
-         "keymap.ss"
-         "prefs.ss")
+         "interfaces.rkt"
+         "display.rkt"
+         "controller.rkt"
+         "keymap.rkt"
+         "prefs.rkt")
 
 (provide syntax-snip%
          marshall-syntax
@@ -167,7 +165,7 @@
 
 ;; SNIPCLASS
 
-;; COPIED AND MODIFIED from mrlib/syntax-browser.ss
+;; COPIED AND MODIFIED from mrlib/syntax-browser.rkt
 (define syntax-snipclass%
   (class snip-class%
     (define/override (read stream)
@@ -178,4 +176,4 @@
 (define snip-class (new syntax-snipclass%))
 (send snip-class set-version 2)
 (send snip-class set-classname
-      (format "~s" '(lib "macro-debugger/syntax-browser/snip.ss")))
+      (format "~s" '(lib "macro-debugger/syntax-browser/snip.rkt")))
diff --git a/collects/macro-debugger/syntax-browser/text.rkt b/collects/macro-debugger/syntax-browser/text.rkt
index 6af632a..839123c 100644
--- a/collects/macro-debugger/syntax-browser/text.rkt
+++ b/collects/macro-debugger/syntax-browser/text.rkt
@@ -1,12 +1,12 @@
-#lang scheme/base
-(require scheme/list
-         scheme/class
-         scheme/gui
+#lang racket/base
+(require racket/list
+         racket/class
+         racket/gui
          drracket/arrow
          framework/framework
          unstable/interval-map
          unstable/gui/notify
-         "interfaces.ss")
+         "interfaces.rkt")
 
 (provide text:hover<%>
          text:hover-drawings<%>
diff --git a/collects/macro-debugger/syntax-browser/util.rkt b/collects/macro-debugger/syntax-browser/util.rkt
index c74553a..1c3ad52 100644
--- a/collects/macro-debugger/syntax-browser/util.rkt
+++ b/collects/macro-debugger/syntax-browser/util.rkt
@@ -1,6 +1,5 @@
-
-#lang scheme/base
-(require scheme/class)
+#lang racket/base
+(require racket/class)
 (provide with-unlock
          make-text-port)
 
diff --git a/collects/macro-debugger/syntax-browser/widget.rkt b/collects/macro-debugger/syntax-browser/widget.rkt
index 30af2e7..5aaccbc 100644
--- a/collects/macro-debugger/syntax-browser/widget.rkt
+++ b/collects/macro-debugger/syntax-browser/widget.rkt
@@ -1,21 +1,20 @@
-#lang scheme/base
-(require scheme/class
-         mred
-         framework/framework
-         scheme/list
-         scheme/match
+#lang racket/base
+(require racket/class
+         racket/gui
+         racket/list
+         racket/match
+         framework
          syntax/id-table
-         (rename-in unstable/class-iop
-                    [send/i send:])
-         "interfaces.ss"
-         "controller.ss"
-         "display.ss"
-         "keymap.ss"
-         "hrule-snip.ss"
-         "properties.ss"
-         "text.ss"
-         "util.ss"
-         "../util/mpi.ss")
+         unstable/class-iop
+         "interfaces.rkt"
+         "controller.rkt"
+         "display.rkt"
+         "keymap.rkt"
+         "hrule-snip.rkt"
+         "properties.rkt"
+         "text.rkt"
+         "util.rkt"
+         "../util/mpi.rkt")
 (provide widget%)
 
 ;; widget%
@@ -33,7 +32,7 @@
       (new panel:horizontal-dragable% (parent -main-panel)))
     (define -text (new browser-text%))
     (define -ecanvas
-      (new editor-canvas% (parent -split-panel) (editor -text)))
+      (new canvas:color% (parent -split-panel) (editor -text)))
     (define -props-panel (new horizontal-panel% (parent -split-panel)))
     (define props
       (new properties-view%
@@ -55,7 +54,7 @@
     (define/private (internal-show-props show?)
       (if show?
           (unless (send -props-panel is-shown?)
-            (let ([p (send: config config<%> get-props-percentage)])
+            (let ([p (send/i config config<%> get-props-percentage)])
               (send -split-panel add-child -props-panel)
               (update-props-percentage p))
             (send -props-panel show #t))
@@ -82,7 +81,7 @@
 
     (define/public (shutdown)
       (when (props-panel-shown?)
-        (send: config config<%> set-props-percentage
+        (send/i config config<%> set-props-percentage
                (cadr (send -split-panel get-percentages)))))
 
     ;; syntax-browser<%> Methods
@@ -115,29 +114,29 @@
                                #:substitutions [substitutions null])
       (let ([display (internal-add-syntax stx)]
             [definite-table (make-hasheq)])
-        (let ([range (send: display display<%> get-range)]
-              [offset (send: display display<%> get-start-position)])
+        (let ([range (send/i display display<%> get-range)]
+              [offset (send/i display display<%> get-start-position)])
           (for ([subst substitutions])
-            (for ([r (send: range range<%> get-ranges (car subst))])
+            (for ([r (send/i range range<%> get-ranges (car subst))])
               (with-unlock -text
                 (send -text insert (cdr subst)
                       (+ offset (car r))
                       (+ offset (cdr r))
                       #f)
                 (send -text change-style
-                      (code-style -text (send: config config<%> get-syntax-font-size))
+                      (code-style -text (send/i config config<%> get-syntax-font-size))
                       (+ offset (car r))
                       (+ offset (cdr r)))))))
         (for ([hi-stxs hi-stxss] [hi-color hi-colors])
-          (send: display display<%> highlight-syntaxes hi-stxs hi-color))
+          (send/i display display<%> highlight-syntaxes hi-stxs hi-color))
         (for ([definite definites])
           (hash-set! definite-table definite #t)
           (when shift-table
             (for ([shifted-definite (hash-ref shift-table definite null)])
               (hash-set! definite-table shifted-definite #t))))
         (let ([binder-table (make-free-id-table)])
-          (define range (send: display display<%> get-range))
-          (define start (send: display display<%> get-start-position))
+          (define range (send/i display display<%> get-range))
+          (define start (send/i display display<%> get-start-position))
           (define (get-binders id)
             (let ([binder (free-id-table-ref binder-table id #f)])
               (cond [(not binder) null]
@@ -149,17 +148,17 @@
           (for ([binder binders])
             (free-id-table-set! binder-table binder binder))
           ;; Underline binders (and shifted binders)
-          (send: display display<%> underline-syntaxes
+          (send/i display display<%> underline-syntaxes
                  (append (apply append (map get-shifted binders))
                          binders))
           ;; Make arrows (& billboards, when enabled)
-          (for ([id (send: range range<%> get-identifier-list)])
+          (for ([id (send/i range range<%> get-identifier-list)])
             (define definite? (hash-ref definite-table id #f))
             (when #f ;; DISABLED
               (add-binding-billboard start range id definite?))
             (for ([binder (get-binders id)])
-              (for ([binder-r (send: range range<%> get-ranges binder)])
-                (for ([id-r (send: range range<%> get-ranges id)])
+              (for ([binder-r (send/i range range<%> get-ranges binder)])
+                (for ([id-r (send/i range range<%> get-ranges id)])
                   (add-binding-arrow start binder-r id-r definite?))))))
         (void)))
 
@@ -187,7 +186,7 @@
                            (+ start (cdr id-r))
                            (string-append "from " (mpi->string src-mod))
                            (if definite? "blue" "purple")))
-                   (send: range range<%> get-ranges id))]
+                   (send/i range range<%> get-ranges id))]
         [_ (void)]))
 
     (define/public (add-separator)
@@ -200,7 +199,7 @@
       (with-unlock -text
         (send -text erase)
         (send -text delete-all-drawings))
-      (send: controller displays-manager<%> remove-all-syntax-displays))
+      (send/i controller displays-manager<%> remove-all-syntax-displays))
 
     (define/public (get-text) -text)
 
@@ -218,7 +217,7 @@
           display)))
 
     (define/private (calculate-columns)
-      (define style (code-style -text (send: config config<%> get-syntax-font-size)))
+      (define style (code-style -text (send/i config config<%> get-syntax-font-size)))
       (define char-width (send style get-text-width (send -ecanvas get-dc)))
       (define-values (canvas-w canvas-h) (send -ecanvas get-client-size))
       (sub1 (inexact->exact (floor (/ canvas-w char-width)))))
@@ -227,13 +226,13 @@
     (super-new)
     (setup-keymap)
 
-    (send: config config<%> listen-props-shown?
+    (send/i config config<%> listen-props-shown?
            (lambda (show?)
              (show-props show?)))
-    (send: config config<%> listen-props-percentage
+    (send/i config config<%> listen-props-percentage
            (lambda (p)
              (update-props-percentage p)))
-    (internal-show-props (send: config config<%> get-props-shown?))))
+    (internal-show-props (send/i config config<%> get-props-shown?))))
 
 
 (define clickback-style
@@ -251,13 +250,20 @@
 ;; Specialized classes for widget
 
 (define browser-text%
-  (class (text:arrows-mixin
-          (text:tacking-mixin
-           (text:hover-drawings-mixin
-            (text:hover-mixin
-             (text:hide-caret/selection-mixin
-              (editor:standard-style-list-mixin text:basic%))))))
-    (inherit set-autowrap-bitmap)
-    (define/override (default-style-name) "Basic")
-    (super-new (auto-wrap #t))
-    (set-autowrap-bitmap #f)))
+  (let ([browser-text-default-style-name "widget.rkt::browser-text% basic"])
+    (class (text:arrows-mixin
+            (text:tacking-mixin
+             (text:hover-drawings-mixin
+              (text:hover-mixin
+               (text:hide-caret/selection-mixin
+                (text:foreground-color-mixin
+                 (editor:standard-style-list-mixin text:basic%)))))))
+      (inherit set-autowrap-bitmap get-style-list)
+      (define/override (default-style-name) browser-text-default-style-name)
+      (super-new (auto-wrap #t))
+      (let* ([sl (get-style-list)]
+             [standard (send sl find-named-style (editor:get-default-color-style-name))]
+             [browser-basic (send sl find-or-create-style standard
+                                  (make-object style-delta% 'change-family 'default))])
+        (send sl new-named-style browser-text-default-style-name browser-basic))
+      (set-autowrap-bitmap #f))))
diff --git a/collects/macro-debugger/util/mpi.rkt b/collects/macro-debugger/util/mpi.rkt
index 6f627aa..5713951 100644
--- a/collects/macro-debugger/util/mpi.rkt
+++ b/collects/macro-debugger/util/mpi.rkt
@@ -1,9 +1,12 @@
-#lang scheme/base
-(require scheme/match)
+#lang racket/base
+(require racket/match
+         racket/string)
 
 (provide mpi->list
-         mpi->string)
+         mpi->string
+         self-mpi?)
 
+;; mpi->list : module-path-index -> list
 (define (mpi->list mpi)
   (cond [(module-path-index? mpi)
          (let-values ([(path relto) (module-path-index-split mpi)])
@@ -18,12 +21,16 @@
   (if (module-path-index? mpi)
       (let ([mps (mpi->list mpi)])
         (cond [(pair? mps)
-               (apply string-append
-                      (format "~s" (car mps))
-                      (map (lambda (x) (format " <= ~s" x)) (cdr mps)))]
+               (string-join (map (lambda (x) (format "~s" x)) mps)
+                            " <= ")]
               [(null? mps) "this module"]))
       (format "~s" mpi)))
 
+;; self-mpi? : module-path-index -> bool
+(define (self-mpi? mpi)
+  (let-values ([(path relto) (module-path-index-split mpi)])
+    (eq? path #f)))
+
 ;; --
 
 (provide mpi->mpi-sexpr
@@ -169,7 +176,7 @@
           [package (string-append (caddr m) ".plt")]
           [version (and (cadddr m) (parse-version (cadddr m)))]
           [path (list-ref m 4)])
-      `(planet ,(string-append (or path "main") ".ss")
+      `(planet ,(string-append (or path "main") ".rkt")
                (,owner ,package . ,version)))))
 
 (define (parse-version str)
@@ -179,7 +186,7 @@
 (define (split-mods* path)
   (let ([mods (split-mods path)])
     (if (and (pair? mods) (null? (cdr mods)))
-        (append mods (list "main.ss"))
+        (append mods (list "main.rkt"))
         mods)))
 
 (define (split-mods path [more null])
diff --git a/collects/macro-debugger/util/stxobj.rkt b/collects/macro-debugger/util/stxobj.rkt
new file mode 100644
index 0000000..58d30f2
--- /dev/null
+++ b/collects/macro-debugger/util/stxobj.rkt
@@ -0,0 +1,30 @@
+#lang racket/base
+(require (rename-in racket/contract [-> c:->])
+         ffi/unsafe)
+
+(define lib (ffi-lib #f))
+
+(define get-marks
+  (get-ffi-obj "scheme_stx_extract_marks" lib
+               (_fun _scheme -> _scheme)))
+
+(define (simplify-marks marklist)
+  (simplify* (sort marklist <)))
+
+(define (simplify* marklist)
+  (cond [(null? marklist) marklist]
+        [(null? (cdr marklist)) marklist]
+        [(= (car marklist) (cadr marklist))
+         (simplify* (cddr marklist))]
+        [else
+         (let ([result (simplify* (cdr marklist))])
+           (if (eq? result (cdr marklist))
+               marklist
+               (cons (car marklist) result)))]))
+
+(provide/contract
+ [get-marks
+  ;; syntax? check needed for safety!
+  (c:-> syntax? any)])
+
+(provide simplify-marks)
diff --git a/collects/macro-debugger/view/cursor.rkt b/collects/macro-debugger/view/cursor.rkt
index a83a8ab..080c1ec 100644
--- a/collects/macro-debugger/view/cursor.rkt
+++ b/collects/macro-debugger/view/cursor.rkt
@@ -1,6 +1,4 @@
-
-#lang scheme/base
-(require scheme/promise)
+#lang racket/base
 (provide cursor?
          cursor-position
          cursor:new
@@ -24,7 +22,8 @@
 
          cursor->list
          cursor:prefix->list
-         cursor:suffix->list)
+         cursor:suffix->list
+         cursor-count)
 
 (define-struct cursor (vector count position)
   #:mutable)
diff --git a/collects/macro-debugger/view/debug-format.rkt b/collects/macro-debugger/view/debug-format.rkt
index 87cdc04..6527397 100644
--- a/collects/macro-debugger/view/debug-format.rkt
+++ b/collects/macro-debugger/view/debug-format.rkt
@@ -1,6 +1,5 @@
-
-#lang scheme/base
-(require scheme/pretty)
+#lang racket/base
+(require racket/pretty)
 (provide write-debug-file
          load-debug-file)
 
diff --git a/collects/macro-debugger/view/debug.rkt b/collects/macro-debugger/view/debug.rkt
index dff2ec1..8ebc9da 100644
--- a/collects/macro-debugger/view/debug.rkt
+++ b/collects/macro-debugger/view/debug.rkt
@@ -1,12 +1,11 @@
-#lang scheme/base
-(require scheme/pretty
-         scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:])
-         "interfaces.ss"
-         "debug-format.ss"
-         "prefs.ss"
-         "view.ss")
+#lang racket/base
+(require racket/pretty
+         racket/class
+         unstable/class-iop
+         "interfaces.rkt"
+         "debug-format.rkt"
+         "prefs.rkt"
+         "view.rkt")
 (provide debug-file)
 
 (define (widget-mixin %)
@@ -30,5 +29,5 @@
     (pretty-print msg)
     (pretty-print ctx)
     (let* ([w (make-stepper)])
-      (send: w widget<%> add-trace events)
+      (send/i w widget<%> add-trace events)
       w)))
diff --git a/collects/macro-debugger/view/extensions.rkt b/collects/macro-debugger/view/extensions.rkt
index 88cd113..61425dc 100644
--- a/collects/macro-debugger/view/extensions.rkt
+++ b/collects/macro-debugger/view/extensions.rkt
@@ -1,27 +1,22 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:]
-                    [send*/i send*:]
-                    [init-field/i init-field:])
-         scheme/unit
-         scheme/list
-         scheme/match
-         scheme/gui
-         framework/framework
-         syntax/boundmap
-         "interfaces.ss"
-         "prefs.ss"
-         "warning.ss"
-         "hiding-panel.ss"
-         (prefix-in s: "../syntax-browser/widget.ss")
-         (prefix-in s: "../syntax-browser/keymap.ss")
-         (prefix-in s: "../syntax-browser/interfaces.ss")
-         "../model/deriv.ss"
-         "../model/deriv-util.ss"
-         "../model/trace.ss"
-         "../model/steps.ss"
-         "cursor.ss"
+#lang racket/base
+(require racket/class
+         racket/unit
+         racket/list
+         racket/match
+         racket/gui
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "prefs.rkt"
+         "hiding-panel.rkt"
+         (prefix-in s: "../syntax-browser/widget.rkt")
+         (prefix-in s: "../syntax-browser/keymap.rkt")
+         (prefix-in s: "../syntax-browser/interfaces.rkt")
+         "../model/deriv.rkt"
+         "../model/deriv-util.rkt"
+         "../model/trace.rkt"
+         "../model/steps.rkt"
+         "cursor.rkt"
          unstable/gui/notify)
 (provide stepper-keymap%
          stepper-syntax-widget%)
@@ -30,7 +25,7 @@
 
 (define stepper-keymap%
   (class s:syntax-keymap%
-    (init-field: (macro-stepper widget<%>))
+    (init-field/i (macro-stepper widget<%>))
     (inherit-field config
                    controller)
     (inherit add-function
@@ -42,17 +37,17 @@
     (super-new)
 
     (define/public (get-hiding-panel)
-      (send: macro-stepper widget<%> get-macro-hiding-prefs))
+      (send/i macro-stepper widget<%> get-macro-hiding-prefs))
 
     (add-function "hiding:show-macro"
                   (lambda (i e)
-                    (send*: (get-hiding-panel) hiding-prefs<%>
+                    (send*/i (get-hiding-panel) hiding-prefs<%>
                       (add-show-identifier)
                       (refresh))))
 
     (add-function "hiding:hide-macro"
                   (lambda (i e)
-                    (send*: (get-hiding-panel) hiding-prefs<%>
+                    (send*/i (get-hiding-panel) hiding-prefs<%>
                       (add-hide-identifier)
                       (refresh))))
 
@@ -78,21 +73,21 @@
 
 (define stepper-syntax-widget%
   (class s:widget%
-    (init-field: (macro-stepper widget<%>))
+    (init-field/i (macro-stepper widget<%>))
     (inherit get-text)
     (inherit-field controller)
 
     (define/override (setup-keymap)
       (new stepper-keymap%
            (editor (get-text))
-           (config (send: macro-stepper widget<%> get-config))
+           (config (send/i macro-stepper widget<%> get-config))
            (controller controller)
            (macro-stepper macro-stepper)))
 
     (define/override (show-props show?)
       (super show-props show?)
-      (send: macro-stepper widget<%> update/preserve-view))
+      (send/i macro-stepper widget<%> update/preserve-view))
 
     (super-new
-     (config (send: macro-stepper widget<%> get-config)))))
+     (config (send/i macro-stepper widget<%> get-config)))))
 
diff --git a/collects/macro-debugger/view/frame.rkt b/collects/macro-debugger/view/frame.rkt
index f86ac94..3d02a47 100644
--- a/collects/macro-debugger/view/frame.rkt
+++ b/collects/macro-debugger/view/frame.rkt
@@ -1,27 +1,23 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [define/i define:]
-                    [send/i send:])
-         scheme/unit
-         scheme/list
-         scheme/file
-         scheme/match
-         scheme/gui
-         framework/framework
-         syntax/boundmap
-         "interfaces.ss"
-         "stepper.ss"
-         "prefs.ss"
-         "warning.ss"
-         "hiding-panel.ss"
-         (prefix-in sb: "../syntax-browser/embed.ss")
-	 (prefix-in sb: "../syntax-browser/interfaces.ss")
-         "../model/deriv.ss"
-         "../model/deriv-util.ss"
-         "../model/trace.ss"
-         "../model/steps.ss"
-         "cursor.ss"
+#lang racket/base
+(require racket/class
+         racket/unit
+         racket/list
+         racket/file
+         racket/match
+         racket/gui
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "stepper.rkt"
+         "prefs.rkt"
+         "hiding-panel.rkt"
+         (prefix-in sb: "../syntax-browser/embed.rkt")
+	 (prefix-in sb: "../syntax-browser/interfaces.rkt")
+         "../model/deriv.rkt"
+         "../model/deriv-util.rkt"
+         "../model/trace.rkt"
+         "../model/steps.rkt"
+         "cursor.rkt"
          unstable/gui/notify)
 (provide macro-stepper-frame-mixin)
 
@@ -49,8 +45,8 @@
              get-help-menu)
 
     (super-new (label (make-label))
-               (width (send: config config<%> get-width))
-               (height (send: config config<%> get-height)))
+               (width (send/i config config<%> get-width))
+               (height (send/i config config<%> get-height)))
 
     (define/private (make-label)
       (if filename
@@ -65,10 +61,10 @@
     ;; to doing something. Avoid unnecessary updates.
     (define-values (w0 h0) (get-size))
     (define/override (on-size w h)
-      (send: config config<%> set-width w)
-      (send: config config<%> set-height h)
+      (send/i config config<%> set-width w)
+      (send/i config config<%> set-height h)
       (unless (and (= w0 w) (= h0 h))
-        (send: widget widget<%> update/preserve-view))
+        (send/i widget widget<%> update/preserve-view))
       (set!-values (w0 h0) (values w h)))
 
     (define warning-panel
@@ -80,13 +76,13 @@
     (define/public (get-macro-stepper-widget%)
       macro-stepper-widget%)
 
-    (define: widget widget<%>
+    (define/i widget widget<%>
       (new (get-macro-stepper-widget%)
            (parent (get-area-container))
            (director director)
            (config config)))
-    (define: controller sb:controller<%>
-      (send: widget widget<%> get-controller))
+    (define/i controller sb:controller<%>
+      (send/i widget widget<%> get-controller))
 
     (define/public (get-widget) widget)
     (define/public (get-controller) controller)
@@ -128,11 +124,11 @@
       (new (get-menu-item%)
            (label "Duplicate stepper")
            (parent file-menu)
-           (callback (lambda _ (send: widget widget<%> duplicate-stepper))))
+           (callback (lambda _ (send/i widget widget<%> duplicate-stepper))))
       (new (get-menu-item%)
            (label "Duplicate stepper (current term only)")
            (parent file-menu)
-           (callback (lambda _ (send: widget widget<%> show-in-new-frame)))))
+           (callback (lambda _ (send/i widget widget<%> show-in-new-frame)))))
 
     (menu-option/notify-box stepper-menu
                             "View syntax properties"
@@ -149,23 +145,23 @@
                               (parent id-menu)
                               (callback
                                (lambda _ 
-                                 (send: controller sb:controller<%> set-identifier=? p))))])
-                    (send: controller sb:controller<%> listen-identifier=?
+                                 (send/i controller sb:controller<%> set-identifier=? p))))])
+                    (send/i controller sb:controller<%> listen-identifier=?
                            (lambda (name+func)
                              (send this-choice check
                                    (eq? (car name+func) (car p)))))))
                 (sb:identifier=-choices)))
 
-    (let ([identifier=? (send: config config<%> get-identifier=?)])
+    (let ([identifier=? (send/i config config<%> get-identifier=?)])
       (when identifier=?
         (let ([p (assoc identifier=? (sb:identifier=-choices))])
-          (send: controller sb:controller<%> set-identifier=? p))))
+          (send/i controller sb:controller<%> set-identifier=? p))))
 
     (new (get-menu-item%)
          (label "Clear selection")
          (parent stepper-menu)
          (callback
-          (lambda _ (send: controller sb:controller<%> 
+          (lambda _ (send/i controller sb:controller<%> 
 			   set-selected-syntax #f))))
 
     (new separator-menu-item% (parent stepper-menu))
@@ -177,11 +173,11 @@
     (new (get-menu-item%)
          (label "Remove selected term")
          (parent stepper-menu)
-         (callback (lambda _ (send: widget widget<%> remove-current-term))))
+         (callback (lambda _ (send/i widget widget<%> remove-current-term))))
     (new (get-menu-item%)
          (label "Reset mark numbering")
          (parent stepper-menu)
-         (callback (lambda _ (send: widget widget<%> reset-primary-partition))))
+         (callback (lambda _ (send/i widget widget<%> reset-primary-partition))))
     (let ([extras-menu
            (new (get-menu%)
                 (label "Extra options")
@@ -191,11 +187,11 @@
            (parent extras-menu)
            (callback
             (lambda (i e)
-              (send: config config<%> set-suffix-option
+              (send/i config config<%> set-suffix-option
                      (if (send i is-checked?)
                          'always
                          'over-limit))
-              (send: widget widget<%> update/preserve-view))))
+              (send/i widget widget<%> update/preserve-view))))
       (menu-option/notify-box extras-menu
                               "Factor out common context?"
                               (get-field split-context? config))
diff --git a/collects/macro-debugger/view/hiding-panel.rkt b/collects/macro-debugger/view/hiding-panel.rkt
index 6522fcd..f8bc2f1 100644
--- a/collects/macro-debugger/view/hiding-panel.rkt
+++ b/collects/macro-debugger/view/hiding-panel.rkt
@@ -1,14 +1,11 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:]
-                    [init-field/i init-field:])
-         scheme/gui
-         scheme/list
-         syntax/boundmap
-         "interfaces.ss"
-         "../model/hiding-policies.ss"
-         "../util/mpi.ss"
+#lang racket/base
+(require racket/class
+         racket/gui
+         racket/list
+         unstable/class-iop
+         "interfaces.rkt"
+         "../model/hiding-policies.rkt"
+         "../util/mpi.rkt"
          unstable/gui/notify)
 (provide macro-hiding-prefs-widget%)
 
@@ -16,12 +13,21 @@
 (define mode:standard "Standard")
 (define mode:custom "Custom ...")
 
+#|
+
+TODO
+
+ - allow entry of more policies
+ - visual feedback on rules applying to selected identifier
+   (need to switch from list to editor)
+
+|#
 
 ;; macro-hiding-prefs-widget%
 (define macro-hiding-prefs-widget%
   (class* object% (hiding-prefs<%>)
     (init parent)
-    (init-field: (stepper widget<%>))
+    (init-field/i (stepper widget<%>))
     (init-field config)
 
     (define/public (get-policy)
@@ -80,7 +86,7 @@
            (style '(deleted))))
 
     (define/private (get-mode)
-      (send: config config<%> get-macro-hiding-mode))
+      (send/i config config<%> get-macro-hiding-mode))
 
     (define/private (macro-hiding-enabled?)
       (let ([mode (get-mode)])
@@ -90,7 +96,7 @@
 
     (define/private (ensure-custom-mode)
       (unless (equal? (get-mode) mode:custom)
-        (send: config config<%> set-macro-hiding-mode mode:custom)))
+        (send/i config config<%> set-macro-hiding-mode mode:custom)))
 
     (define/private (update-visibility)
       (let ([customizing (equal? (get-mode) mode:custom)])
@@ -105,10 +111,10 @@
                             (list customize-panel)
                             null))))))
 
-    (send: config config<%> listen-macro-hiding-mode
-           (lambda (value)
-             (update-visibility)
-             (force-refresh)))
+    (send/i config config<%> listen-macro-hiding-mode
+            (lambda (value)
+              (update-visibility)
+              (force-refresh)))
 
     (define box:hiding
       (new check-box%
@@ -176,11 +182,11 @@
     ;; refresh : -> void
     (define/public (refresh)
       (when (macro-hiding-enabled?)
-        (send: stepper widget<%> refresh/resynth)))
+        (send/i stepper widget<%> refresh/resynth)))
 
     ;; force-refresh : -> void
     (define/private (force-refresh)
-      (send: stepper widget<%> refresh/resynth))
+      (send/i stepper widget<%> refresh/resynth))
 
     ;; set-syntax : syntax/#f -> void
     (define/public (set-syntax lstx)
@@ -255,11 +261,13 @@
   (match condition
     [`(free=? ,id)
      (let ([b (identifier-binding id)])
-       (or #;(identifier->string id)
+       (or #| (identifier->string id) |#
            (cond [(list? b)
                   (let ([mod (caddr b)]
                         [name (cadddr b)])
-                    (format "'~s' from ~a" name (mpi->string mod)))]
+                    (if (self-mpi? mod)
+                        (format "'~a' defined in this module" name)
+                        (format "'~s' imported from ~a" name (mpi->string mod))))]
                  [else
                   (symbol->string (syntax-e id))])))]
     [_
diff --git a/collects/macro-debugger/view/interfaces.rkt b/collects/macro-debugger/view/interfaces.rkt
index 270e406..e038725 100644
--- a/collects/macro-debugger/view/interfaces.rkt
+++ b/collects/macro-debugger/view/interfaces.rkt
@@ -1,6 +1,6 @@
-#lang scheme/base
+#lang racket/base
 (require unstable/class-iop
-         (prefix-in sb: "../syntax-browser/interfaces.ss"))
+         (prefix-in sb: "../syntax-browser/interfaces.rkt"))
 (provide (all-defined-out))
 
 (define-interface config<%> (sb:config<%>)
@@ -62,6 +62,7 @@
   (get-raw-deriv
    get-deriv-hidden?
    get-step-index
+   get-step-count
    invalidate-synth!
    invalidate-steps!
 
diff --git a/collects/macro-debugger/view/prefs.rkt b/collects/macro-debugger/view/prefs.rkt
index 39100ed..237d86a 100644
--- a/collects/macro-debugger/view/prefs.rkt
+++ b/collects/macro-debugger/view/prefs.rkt
@@ -1,8 +1,8 @@
-#lang scheme/base
-(require scheme/class
-         framework/framework
-         "interfaces.ss"
-         "../syntax-browser/prefs.ss"
+#lang racket/base
+(require racket/class
+         framework
+         "interfaces.rkt"
+         "../syntax-browser/prefs.rkt"
          unstable/gui/notify
          unstable/gui/prefs)
 (provide pref:macro-step-limit
diff --git a/collects/macro-debugger/view/step-display.rkt b/collects/macro-debugger/view/step-display.rkt
index 075c0d1..0e01ccf 100644
--- a/collects/macro-debugger/view/step-display.rkt
+++ b/collects/macro-debugger/view/step-display.rkt
@@ -1,31 +1,26 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:]
-                    [send*/i send*:]
-                    [init-field/i init-field:])
-         scheme/unit
-         scheme/list
-         scheme/match
-         scheme/gui
-         framework/framework
-         syntax/boundmap
-         "interfaces.ss"
-         "prefs.ss"
-         "extensions.ss"
-         "warning.ss"
-         "hiding-panel.ss"
-         "../model/deriv.ss"
-         "../model/deriv-util.ss"
-         "../model/deriv-parser.ss"
-         "../model/trace.ss"
-         "../model/reductions-config.ss"
-         "../model/reductions.ss"
-         "../model/steps.ss"
+#lang racket/base
+(require racket/class
+         racket/unit
+         racket/list
+         racket/match
+         racket/gui
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "prefs.rkt"
+         "extensions.rkt"
+         "hiding-panel.rkt"
+         "../model/deriv.rkt"
+         "../model/deriv-util.rkt"
+         "../model/deriv-parser.rkt"
+         "../model/trace.rkt"
+         "../model/reductions-config.rkt"
+         "../model/reductions.rkt"
+         "../model/steps.rkt"
          unstable/gui/notify
-	 (prefix-in sb: "../syntax-browser/interfaces.ss")
-         "cursor.ss"
-         "debug-format.ss")
+	 (prefix-in sb: "../syntax-browser/interfaces.rkt")
+         "cursor.rkt"
+         "debug-format.rkt")
 
 #;
 (provide step-display%
@@ -42,23 +37,23 @@
 (define step-display%
   (class* object% (step-display<%>)
 
-    (init-field: (config config<%>))
+    (init-field/i (config config<%>))
     (init-field ((sbview syntax-widget)))
     (super-new)
 
     (define/public (add-internal-error part exn stx events)
-      (send: sbview sb:syntax-browser<%> add-text
-             (if part
-                 (format "Macro stepper error (~a)" part)
-                 "Macro stepper error"))
+      (send/i sbview sb:syntax-browser<%> add-text
+              (if part
+                  (format "Macro stepper error (~a)" part)
+                  "Macro stepper error"))
       (when (exn? exn)
-        (send: sbview sb:syntax-browser<%> add-text " ")
-        (send: sbview sb:syntax-browser<%> add-clickback "[details]"
-               (lambda _ (show-internal-error-details exn events))))
-      (send: sbview sb:syntax-browser<%> add-text ".  ")
-      (when stx (send: sbview sb:syntax-browser<%> add-text "Original syntax:"))
-      (send: sbview sb:syntax-browser<%> add-text "\n")
-      (when stx (send: sbview sb:syntax-browser<%> add-syntax stx)))
+        (send/i sbview sb:syntax-browser<%> add-text " ")
+        (send/i sbview sb:syntax-browser<%> add-clickback "[details]"
+                (lambda _ (show-internal-error-details exn events))))
+      (send/i sbview sb:syntax-browser<%> add-text ".  ")
+      (when stx (send/i sbview sb:syntax-browser<%> add-text "Original syntax:"))
+      (send/i sbview sb:syntax-browser<%> add-text "\n")
+      (when stx (send/i sbview sb:syntax-browser<%> add-syntax stx)))
 
     (define/private (show-internal-error-details exn events)
       (case (message-box/custom "Macro stepper internal error"
@@ -77,7 +72,7 @@
         ((3 #f) (void))))
 
     (define/public (add-error exn)
-      (send*: sbview sb:syntax-browser<%>
+      (send*/i sbview sb:syntax-browser<%>
         (add-error-text (exn-message exn))
         (add-text "\n")))
 
@@ -87,6 +82,8 @@
              (show-step step shift-table)]
             [(misstep? step)
              (show-misstep step shift-table)]
+            [(remarkstep? step)
+             (show-remarkstep step shift-table)]
             [(prestep? step)
              (show-prestep step shift-table)]
             [(poststep? step)
@@ -96,17 +93,17 @@
                                #:binders [binders null]
                                #:definites [definites null]
                                #:shift-table [shift-table #f])
-      (send: sbview sb:syntax-browser<%> add-syntax stx
-             #:binders binders
-             #:definites definites
-             #:shift-table shift-table))
+      (send/i sbview sb:syntax-browser<%> add-syntax stx
+              #:binders binders
+              #:definites definites
+              #:shift-table shift-table))
 
     (define/public (add-final stx error
                               #:binders binders
                               #:definites definites
                               #:shift-table [shift-table #f])
       (when stx
-        (send*: sbview sb:syntax-browser<%>
+        (send*/i sbview sb:syntax-browser<%>
           (add-text "Expansion finished\n")
           (add-syntax stx
                       #:binders binders
@@ -120,8 +117,8 @@
       (define state (protostep-s1 step))
       (define lctx (state-lctx state))
       (for ([bf lctx])
-        (send: sbview sb:syntax-browser<%> add-text 
-               "\nwhile executing macro transformer in:\n")
+        (send/i sbview sb:syntax-browser<%> add-text 
+                "\nwhile executing macro transformer in:\n")
         (insert-syntax/redex (bigframe-term bf)
                              (bigframe-foci bf)
                              (state-binders state)
@@ -150,7 +147,7 @@
         (show-lctx step shift-table)))
 
     (define/private (factor-common-context state1 state2)
-      (if (send: config config<%> get-split-context?)
+      (if (send/i config config<%> get-split-context?)
           (factor-common-context* state1 state2)
           (values null state1 state2)))
 
@@ -177,7 +174,7 @@
       (when (pair? ctx)
         (let* ([hole-stx #'~~HOLE~~]
                [the-syntax (context-fill ctx hole-stx)])
-          (send*: sbview sb:syntax-browser<%>
+          (send*/i sbview sb:syntax-browser<%>
             (add-text "\nin context:\n")
             (add-syntax the-syntax
                         #:definites uses1
@@ -218,30 +215,46 @@
       (define state (protostep-s1 step))
       (show-state/redex state shift-table)
       (separator step)
-      (send*: sbview sb:syntax-browser<%>
+      (send*/i sbview sb:syntax-browser<%>
         (add-error-text (exn-message (misstep-exn step)))
         (add-text "\n"))
       (when (exn:fail:syntax? (misstep-exn step))
         (for ([e (exn:fail:syntax-exprs (misstep-exn step))])
-          (send: sbview sb:syntax-browser<%> add-syntax e
-                 #:binders (or (state-binders state) null)
-                 #:definites (or (state-uses state) null)
-                 #:shift-table shift-table)))
+          (send/i sbview sb:syntax-browser<%> add-syntax e
+                  #:binders (or (state-binders state) null)
+                  #:definites (or (state-uses state) null)
+                  #:shift-table shift-table)))
+      (show-lctx step shift-table))
+
+    (define/private (show-remarkstep step shift-table)
+      (define state (protostep-s1 step))
+      (for ([content (in-list (remarkstep-contents step))])
+        (cond [(string? content)
+               (send*/i sbview sb:syntax-browser<%>
+                       (add-text content)
+                       (add-text "\n"))]
+              [(syntax? content)
+               (send*/i sbview sb:syntax-browser<%>
+                 (add-syntax content
+                             #:binders (or (state-binders state) null)
+                             #:definites (or (state-uses state) null)
+                             #:shift-table shift-table)
+                 (add-text "\n"))]))
       (show-lctx step shift-table))
 
     ;; insert-syntax/color
     (define/private (insert-syntax/color stx foci binders shift-table
                                          definites frontier hi-color)
-      (define highlight-foci? (send: config config<%> get-highlight-foci?))
-      (define highlight-frontier? (send: config config<%> get-highlight-frontier?))
-      (send: sbview sb:syntax-browser<%> add-syntax stx
-             #:definites (or definites null)
-             #:binders binders
-             #:shift-table shift-table
-             #:hi-colors (list hi-color
-                               "WhiteSmoke")
-             #:hi-stxss (list (if highlight-foci? foci null)
-                              (if highlight-frontier? frontier null))))
+      (define highlight-foci? (send/i config config<%> get-highlight-foci?))
+      (define highlight-frontier? (send/i config config<%> get-highlight-frontier?))
+      (send/i sbview sb:syntax-browser<%> add-syntax stx
+              #:definites (or definites null)
+              #:binders binders
+              #:shift-table shift-table
+              #:hi-colors (list hi-color
+                                "WhiteSmoke")
+              #:hi-stxss (list (if highlight-foci? foci null)
+                               (if highlight-frontier? frontier null))))
 
     ;; insert-syntax/redex
     (define/private (insert-syntax/redex stx foci binders shift-table
@@ -257,7 +270,7 @@
 
     ;; insert-step-separator : string -> void
     (define/private (insert-step-separator text)
-      (send*: sbview sb:syntax-browser<%>
+      (send*/i sbview sb:syntax-browser<%>
         (add-text "\n    ")
         (add-text
          (make-object image-snip% 
@@ -269,14 +282,14 @@
 
     ;; insert-as-separator : string -> void
     (define/private (insert-as-separator text)
-      (send*: sbview sb:syntax-browser<%>
+      (send*/i sbview sb:syntax-browser<%>
         (add-text "\n    ")
         (add-text text)
         (add-text "\n\n")))
 
     ;; insert-step-separator/small : string -> void
     (define/private (insert-step-separator/small text)
-      (send*: sbview sb:syntax-browser<%>
+      (send*/i sbview sb:syntax-browser<%>
         (add-text "    ")
         (add-text
          (make-object image-snip% 
diff --git a/collects/macro-debugger/view/stepper.rkt b/collects/macro-debugger/view/stepper.rkt
index f4f2e5f..bba35c7 100644
--- a/collects/macro-debugger/view/stepper.rkt
+++ b/collects/macro-debugger/view/stepper.rkt
@@ -1,30 +1,24 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [define/i define:]
-                    [send/i send:]
-                    [send*/i send*:]
-                    [init-field/i init-field:])
-         scheme/unit
-         scheme/list
-         scheme/match
-         scheme/gui
-         framework/framework
-         syntax/boundmap
-         "interfaces.ss"
-         "prefs.ss"
-         "extensions.ss"
-         "warning.ss"
-         "hiding-panel.ss"
-         "term-record.ss"
-         "step-display.ss"
-	 (prefix-in sb: "../syntax-browser/interfaces.ss")
-         "../model/deriv.ss"
-         "../model/deriv-util.ss"
-         "../model/trace.ss"
-         "../model/reductions.ss"
-         "../model/steps.ss"
-         "cursor.ss"
+#lang racket/base
+(require racket/class
+         racket/unit
+         racket/list
+         racket/match
+         racket/gui
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "prefs.rkt"
+         "extensions.rkt"
+         "hiding-panel.rkt"
+         "term-record.rkt"
+         "step-display.rkt"
+	 (prefix-in sb: "../syntax-browser/interfaces.rkt")
+         "../model/deriv.rkt"
+         "../model/deriv-util.rkt"
+         "../model/trace.rkt"
+         "../model/reductions.rkt"
+         "../model/steps.rkt"
+         "cursor.rkt"
          unstable/gui/notify
          (only-in mzscheme [#%top-interaction mz-top-interaction]))
 (provide macro-stepper-widget%
@@ -37,7 +31,7 @@
   (class* object% (widget<%>)
     (init-field parent)
     (init-field config)
-    (init-field: (director director<%>))
+    (init-field/i (director director<%>))
 
     ;; Terms
 
@@ -70,7 +64,7 @@
     (define/public (add trec)
       (set! all-terms (cons trec all-terms))
       (let ([display-new-term? (cursor:at-end? terms)]
-            [invisible? (send: trec term-record<%> get-deriv-hidden?)])
+            [invisible? (send/i trec term-record<%> get-deriv-hidden?)])
         (unless invisible?
           (cursor:add-to-end! terms (list trec))
           (trim-navigator)
@@ -88,26 +82,25 @@
     (define/public (show-in-new-frame)
       (let ([term (focused-term)])
         (when term
-          (let ([new-stepper (send: director director<%> new-stepper '(no-new-traces))])
-            (send: new-stepper widget<%> add-deriv (send: term term-record<%> get-raw-deriv))
+          (let ([new-stepper (send/i director director<%> new-stepper '(no-new-traces))])
+            (send/i new-stepper widget<%> add-deriv (send/i term term-record<%> get-raw-deriv))
             (void)))))
 
     ;; duplicate-stepper : -> void
     (define/public (duplicate-stepper)
-      (let ([new-stepper (send: director director<%> new-stepper)])
+      (let ([new-stepper (send/i director director<%> new-stepper)])
         (for ([term (cursor->list terms)])
-          (send: new-stepper widget<%> add-deriv
-                 (send: term term-record<%> get-raw-deriv)))))
+          (send/i new-stepper widget<%> add-deriv
+                 (send/i term term-record<%> get-raw-deriv)))))
 
     (define/public (get-config) config)
     (define/public (get-controller) sbc)
     (define/public (get-view) sbview)
     (define/public (get-step-displayer) step-displayer)
-    (define/public (get-warnings-area) warnings-area)
     (define/public (get-macro-hiding-prefs) macro-hiding-prefs)
 
     (define/public (reset-primary-partition)
-      (send: sbc sb:controller<%> reset-primary-partition)
+      (send/i sbc sb:controller<%> reset-primary-partition)
       (update/preserve-view))
 
     (define area (new vertical-panel% (parent parent)))
@@ -129,31 +122,29 @@
            (stretchable-height #f)
            (alignment '(left center))
            (style '(deleted))))
-    
-    (define warnings-area (new stepper-warnings% (parent area)))
-    
-    (define: sbview sb:syntax-browser<%>
+
+    (define/i sbview sb:syntax-browser<%>
       (new stepper-syntax-widget% 
            (parent area)
            (macro-stepper this)))
-    (define: step-displayer step-display<%>
+    (define/i step-displayer step-display<%>
       (new step-display%
            (config config)
            (syntax-widget sbview)))
-    (define: sbc sb:controller<%>
-      (send: sbview sb:syntax-browser<%> get-controller))
+    (define/i sbc sb:controller<%>
+      (send/i sbview sb:syntax-browser<%> get-controller))
     (define control-pane
       (new vertical-panel% (parent area) (stretchable-height #f)))
-    (define: macro-hiding-prefs hiding-prefs<%>
+    (define/i macro-hiding-prefs hiding-prefs<%>
       (new macro-hiding-prefs-widget%
            (parent control-pane)
            (stepper this)
            (config config)))
 
-    (send: sbc sb:controller<%>
+    (send/i sbc sb:controller<%>
            listen-selected-syntax
-           (lambda (stx) (send: macro-hiding-prefs hiding-prefs<%> set-syntax stx)))
-    (send*: config config<%>
+           (lambda (stx) (send/i macro-hiding-prefs hiding-prefs<%> set-syntax stx)))
+    (send*/i config config<%>
       (listen-show-hiding-panel?
        (lambda (show?) (show-macro-hiding-panel show?)))
       (listen-split-context?
@@ -206,7 +197,16 @@
                          (navigate-to (sub1 step))]
                         [(equal? value "end")
                          (navigate-to-end)])))))))
+
+    (define nav:step-count
+      (new message%
+           (label "")
+           (parent extra-navigator)
+           (auto-resize #t)
+           (stretchable-width #f)
+           (stretchable-height #f)))
     (send nav:text set-value "")
+
     (listen-current-step-index
      (lambda (n)
        (send nav:text set-value
@@ -246,34 +246,34 @@
     ;; Navigation
 #|
     (define/public-final (at-start?)
-      (send: (focused-term) term-record<%> at-start?))
+      (send/i (focused-term) term-record<%> at-start?))
     (define/public-final (at-end?)
-      (send: (focused-term) term-record<%> at-end?))
+      (send/i (focused-term) term-record<%> at-end?))
 |#
     (define/public-final (navigate-to-start)
-      (send: (focused-term) term-record<%> navigate-to-start)
+      (send/i (focused-term) term-record<%> navigate-to-start)
       (update/save-position))
     (define/public-final (navigate-to-end)
-      (send: (focused-term) term-record<%> navigate-to-end)
+      (send/i (focused-term) term-record<%> navigate-to-end)
       (update/save-position))
     (define/public-final (navigate-previous)
-      (send: (focused-term) term-record<%> navigate-previous)
+      (send/i (focused-term) term-record<%> navigate-previous)
       (update/save-position))
     (define/public-final (navigate-next)
-      (send: (focused-term) term-record<%> navigate-next)
+      (send/i (focused-term) term-record<%> navigate-next)
       (update/save-position))
     (define/public-final (navigate-to n)
-      (send: (focused-term) term-record<%> navigate-to n)
+      (send/i (focused-term) term-record<%> navigate-to n)
       (update/save-position))
 
     (define/public-final (navigate-up)
       (when (focused-term)
-        (send: (focused-term) term-record<%> on-lose-focus))
+        (send/i (focused-term) term-record<%> on-lose-focus))
       (cursor:move-prev terms)
       (refresh/move))
     (define/public-final (navigate-down)
       (when (focused-term)
-        (send: (focused-term) term-record<%> on-lose-focus))
+        (send/i (focused-term) term-record<%> on-lose-focus))
       (cursor:move-next terms)
       (refresh/move))
 
@@ -285,7 +285,7 @@
 
     ;; update/preserve-lines-view : -> void
     (define/public (update/preserve-lines-view)
-      (define text (send: sbview sb:syntax-browser<%> get-text))
+      (define text (send/i sbview sb:syntax-browser<%> get-text))
       (define start-box (box 0))
       (define end-box (box 0))
       (send text get-visible-line-range start-box end-box)
@@ -298,7 +298,7 @@
 
     ;; update/preserve-view : -> void
     (define/public (update/preserve-view)
-      (define text (send: sbview sb:syntax-browser<%> get-text))
+      (define text (send/i sbview sb:syntax-browser<%> get-text))
       (define start-box (box 0))
       (define end-box (box 0))
       (send text get-visible-position-range start-box end-box)
@@ -308,17 +308,17 @@
     ;; update : -> void
     ;; Updates the terms in the syntax browser to the current step
     (define/private (update)
-      (define text (send: sbview sb:syntax-browser<%> get-text))
+      (define text (send/i sbview sb:syntax-browser<%> get-text))
       (define position-of-interest 0)
       (define multiple-terms? (> (length (cursor->list terms)) 1))
       (send text begin-edit-sequence #f)
-      (send: sbview sb:syntax-browser<%> erase-all)
+      (send/i sbview sb:syntax-browser<%> erase-all)
 
       (update:show-prefix)
-      (when multiple-terms? (send: sbview sb:syntax-browser<%> add-separator))
+      (when multiple-terms? (send/i sbview sb:syntax-browser<%> add-separator))
       (set! position-of-interest (send text last-position))
       (update:show-current-step)
-      (when multiple-terms? (send: sbview sb:syntax-browser<%> add-separator))
+      (when multiple-terms? (send/i sbview sb:syntax-browser<%> add-separator))
       (update:show-suffix)
       (send text end-edit-sequence)
       (send text scroll-to-position
@@ -332,35 +332,35 @@
     ;; update:show-prefix : -> void
     (define/private (update:show-prefix)
       ;; Show the final terms from the cached synth'd derivs
-      (for-each (lambda (trec) (send: trec term-record<%> display-final-term))
+      (for-each (lambda (trec) (send/i trec term-record<%> display-final-term))
                 (cursor:prefix->list terms)))
 
     ;; update:show-current-step : -> void
     (define/private (update:show-current-step)
       (when (focused-term)
-        (send: (focused-term) term-record<%> display-step)))
+        (send/i (focused-term) term-record<%> display-step)))
 
     ;; update:show-suffix : -> void
     (define/private (update:show-suffix)
       (let ([suffix0 (cursor:suffix->list terms)])
         (when (pair? suffix0)
           (for-each (lambda (trec)
-                      (send: trec term-record<%> display-initial-term))
+                      (send/i trec term-record<%> display-initial-term))
                     (cdr suffix0)))))
 
     ;; update-nav-index : -> void
     (define/private (update-nav-index)
       (define term (focused-term))
       (set-current-step-index
-       (and term (send: term term-record<%> get-step-index))))
+       (and term (send/i term term-record<%> get-step-index))))
 
     ;; enable/disable-buttons : -> void
     (define/private (enable/disable-buttons)
       (define term (focused-term))
-      (send nav:start enable (and term (send: term term-record<%> has-prev?)))
-      (send nav:previous enable (and term (send: term term-record<%> has-prev?)))
-      (send nav:next enable (and term (send: term term-record<%> has-next?)))
-      (send nav:end enable (and term (send: term term-record<%> has-next?)))
+      (send nav:start enable (and term (send/i term term-record<%> has-prev?)))
+      (send nav:previous enable (and term (send/i term term-record<%> has-prev?)))
+      (send nav:next enable (and term (send/i term term-record<%> has-next?)))
+      (send nav:end enable (and term (send/i term term-record<%> has-next?)))
       (send nav:text enable (and term #t))
       (send nav:up enable (cursor:has-prev? terms))
       (send nav:down enable (cursor:has-next? terms)))
@@ -370,14 +370,14 @@
     ;; refresh/resynth : -> void
     ;; Macro hiding policy has changed; invalidate cached parts of trec
     (define/public (refresh/resynth)
-      (for-each (lambda (trec) (send: trec term-record<%> invalidate-synth!))
+      (for-each (lambda (trec) (send/i trec term-record<%> invalidate-synth!))
                 (cursor->list terms))
       (refresh))
 
     ;; refresh/re-reduce : -> void
     ;; Reduction config has changed; invalidate cached parts of trec
     (define/private (refresh/re-reduce)
-      (for-each (lambda (trec) (send: trec term-record<%> invalidate-steps!))
+      (for-each (lambda (trec) (send/i trec term-record<%> invalidate-steps!))
                 (cursor->list terms))
       (refresh))
 
@@ -388,9 +388,15 @@
 
     ;; refresh : -> void
     (define/public (refresh)
-      (send warnings-area clear)
       (when (focused-term)
-        (send: (focused-term) term-record<%> on-get-focus))
+        (send/i (focused-term) term-record<%> on-get-focus))
+      (send nav:step-count set-label "")
+      (let ([term (focused-term)])
+        (when term
+          (let ([step-count (send/i term term-record<%> get-step-count)])
+            (when step-count
+              ;; +1 for end of expansion "step"
+              (send nav:step-count set-label (format "of ~s" (add1 step-count)))))))
       (update))
 
     (define/private (foci x) (if (list? x) x (list x)))
@@ -398,7 +404,7 @@
     ;; Hiding policy
     
     (define/public (get-show-macro?)
-      (send: macro-hiding-prefs hiding-prefs<%> get-policy))
+      (send/i macro-hiding-prefs hiding-prefs<%> get-policy))
 
     ;; Derivation pre-processing
 
@@ -407,8 +413,8 @@
     ;; Initialization
 
     (super-new)
-    (show-macro-hiding-panel (send: config config<%> get-show-hiding-panel?))
-    (show-extra-navigation (send: config config<%> get-extra-navigation?))
+    (show-macro-hiding-panel (send/i config config<%> get-show-hiding-panel?))
+    (show-extra-navigation (send/i config config<%> get-extra-navigation?))
     (refresh/move)
     ))
 
diff --git a/collects/macro-debugger/view/term-record.rkt b/collects/macro-debugger/view/term-record.rkt
index 1839dfd..44d7a9c 100644
--- a/collects/macro-debugger/view/term-record.rkt
+++ b/collects/macro-debugger/view/term-record.rkt
@@ -1,33 +1,28 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [define/i define:]
-                    [send/i send:]
-                    [init-field/i init-field:])
-         scheme/unit
-         scheme/list
-         scheme/match
-         scheme/gui
-         framework/framework
-         syntax/boundmap
+#lang racket/base
+(require racket/class
+         racket/unit
+         racket/list
+         racket/match
+         racket/gui
+         framework
          syntax/stx
          unstable/find
-         "interfaces.ss"
-         "prefs.ss"
-         "extensions.ss"
-         "warning.ss"
-         "hiding-panel.ss"
-         "step-display.ss"
-         "../model/deriv.ss"
-         "../model/deriv-util.ss"
-         "../model/deriv-parser.ss"
-         "../model/trace.ss"
-         "../model/reductions-config.ss"
-         "../model/reductions.ss"
-         "../model/steps.ss"
+         unstable/class-iop
+         "interfaces.rkt"
+         "prefs.rkt"
+         "extensions.rkt"
+         "hiding-panel.rkt"
+         "step-display.rkt"
+         "../model/deriv.rkt"
+         "../model/deriv-util.rkt"
+         "../model/deriv-parser.rkt"
+         "../model/trace.rkt"
+         "../model/reductions-config.rkt"
+         "../model/reductions.rkt"
+         "../model/steps.rkt"
          unstable/gui/notify
-         "cursor.ss"
-         "debug-format.ss")
+         "cursor.rkt"
+         "debug-format.rkt")
 
 (provide term-record%)
 
@@ -35,12 +30,12 @@
 
 (define term-record%
   (class* object% (term-record<%>)
-    (init-field: (stepper widget<%>))
+    (init-field/i (stepper widget<%>))
 
-    (define: config config<%>
-      (send: stepper widget<%> get-config))
-    (define: displayer step-display<%>
-      (send: stepper widget<%> get-step-displayer))
+    (define/i config config<%>
+      (send/i stepper widget<%> get-config))
+    (define/i displayer step-display<%>
+      (send/i stepper widget<%> get-step-displayer))
 
     ;; Data
     
@@ -134,7 +129,7 @@
       (unless (or deriv deriv-hidden?)
         (recache-raw-deriv!)
         (when raw-deriv
-          (let ([process (send: stepper widget<%> get-preprocess-deriv)])
+          (let ([process (send/i stepper widget<%> get-preprocess-deriv)])
             (let ([d (process raw-deriv)])
               (when (not d)
                 (set! deriv-hidden? #t))
@@ -151,7 +146,7 @@
       (unless (or raw-steps raw-steps-oops)
         (recache-synth!)
         (when deriv
-          (let ([show-macro? (or (send: stepper widget<%> get-show-macro?)
+          (let ([show-macro? (or (send/i stepper widget<%> get-show-macro?)
                                  (lambda (id) #t))])
             (with-handlers ([(lambda (e) #t)
                              (lambda (e)
@@ -173,12 +168,12 @@
           (set! steps
                 (and raw-steps
                      (let* ([filtered-steps 
-                             (if (send: config config<%> get-show-rename-steps?)
+                             (if (send/i config config<%> get-show-rename-steps?)
                                  raw-steps
                                  (filter (lambda (x) (not (rename-step? x)))
                                          raw-steps))]
                             [processed-steps
-                             (if (send: config config<%> get-one-by-one?)
+                             (if (send/i config config<%> get-one-by-one?)
                                  (reduce:one-by-one filtered-steps)
                                  filtered-steps)])
                        (cursor:new processed-steps))))
@@ -207,7 +202,11 @@
       (and (get-steps) (not (cursor:at-end? (get-steps)))))
 
     (define/public-final (get-step-index)
-      (and (get-steps) (cursor-position (get-steps))))
+      (let ([steps (get-steps)])
+        (and steps (cursor-position steps))))
+    (define/public-final (get-step-count)
+      (let ([steps (get-steps)])
+        (and steps (cursor-count steps))))
 
     (define/public-final (navigate-to-start)
       (cursor:move-to-start (get-steps))
@@ -276,21 +275,21 @@
     ;; display-initial-term : -> void
     (define/public (display-initial-term)
       (cond [raw-deriv-oops
-             (send: displayer step-display<%> add-internal-error
-                    "derivation" raw-deriv-oops #f events)]
+             (send/i displayer step-display<%> add-internal-error
+                     "derivation" raw-deriv-oops #f events)]
             [else
-             (send: displayer step-display<%> add-syntax (wderiv-e1 deriv))]))
+             (send/i displayer step-display<%> add-syntax (wderiv-e1 deriv))]))
 
     ;; display-final-term : -> void
     (define/public (display-final-term)
       (recache-steps!)
       (cond [(syntax? raw-steps-estx)
-             (send: displayer step-display<%> add-syntax raw-steps-estx
-                    #:binders raw-steps-binders
-                    #:shift-table shift-table
-                    #:definites raw-steps-definites)]
+             (send/i displayer step-display<%> add-syntax raw-steps-estx
+                     #:binders raw-steps-binders
+                     #:shift-table shift-table
+                     #:definites raw-steps-definites)]
             [(exn? raw-steps-exn)
-             (send: displayer step-display<%> add-error raw-steps-exn)]
+             (send/i displayer step-display<%> add-error raw-steps-exn)]
             [else (display-oops #f)]))
 
     ;; display-step : -> void
@@ -299,24 +298,24 @@
       (cond [steps
              (let ([step (cursor:next steps)])
                (if step
-                   (send: displayer step-display<%> add-step step
-                          #:shift-table shift-table)
-                   (send: displayer step-display<%> add-final raw-steps-estx raw-steps-exn
-                          #:binders raw-steps-binders
-                          #:shift-table shift-table
-                          #:definites raw-steps-definites)))]
+                   (send/i displayer step-display<%> add-step step
+                           #:shift-table shift-table)
+                   (send/i displayer step-display<%> add-final raw-steps-estx raw-steps-exn
+                           #:binders raw-steps-binders
+                           #:shift-table shift-table
+                           #:definites raw-steps-definites)))]
             [else (display-oops #t)]))
 
     ;; display-oops : boolean -> void
     (define/private (display-oops show-syntax?)
       (cond [raw-steps-oops
-             (send: displayer step-display<%> add-internal-error
-                    "steps" raw-steps-oops
-                    (and show-syntax? (wderiv-e1 deriv))
-                    events)]
+             (send/i displayer step-display<%> add-internal-error
+                     "steps" raw-steps-oops
+                     (and show-syntax? (wderiv-e1 deriv))
+                     events)]
             [raw-deriv-oops
-             (send: displayer step-display<%> add-internal-error
-                    "derivation" raw-deriv-oops #f events)]
+             (send/i displayer step-display<%> add-internal-error
+                     "derivation" raw-deriv-oops #f events)]
             [else
              (error 'term-record::display-oops "internal error")]))
     ))
diff --git a/collects/macro-debugger/view/view.rkt b/collects/macro-debugger/view/view.rkt
index 7162a98..4552b48 100644
--- a/collects/macro-debugger/view/view.rkt
+++ b/collects/macro-debugger/view/view.rkt
@@ -1,14 +1,13 @@
-#lang scheme/base
-(require scheme/class
-         (rename-in unstable/class-iop
-                    [send/i send:])
-         scheme/pretty
-         scheme/gui
-         framework/framework
-         "interfaces.ss"
-         "frame.ss"
-         "prefs.ss"
-         "../model/trace.ss")
+#lang racket/base
+(require racket/class
+         racket/pretty
+         racket/gui
+         framework
+         unstable/class-iop
+         "interfaces.rkt"
+         "frame.rkt"
+         "prefs.rkt"
+         "../model/trace.rkt")
 (provide macro-stepper-director%
          macro-stepper-frame%
          go)
@@ -28,23 +27,23 @@
       (hash-for-each stepper-frames
                      (lambda (stepper-frame flags)
                        (unless (memq 'no-obsolete flags)
-                         (send: stepper-frame stepper-frame<%> add-obsoleted-warning)))))
+                         (send/i stepper-frame stepper-frame<%> add-obsoleted-warning)))))
     (define/public (add-trace events)
       (hash-for-each stepper-frames
                      (lambda (stepper-frame flags)
                        (unless (memq 'no-new-traces flags)
-                         (send: (send: stepper-frame stepper-frame<%> get-widget) widget<%>
+                         (send/i (send/i stepper-frame stepper-frame<%> get-widget) widget<%>
                                 add-trace events)))))
     (define/public (add-deriv deriv)
       (hash-for-each stepper-frames
                      (lambda (stepper-frame flags)
                        (unless (memq 'no-new-traces flags)
-                         (send: (send: stepper-frame stepper-frame<%> get-widget) widget<%>
+                         (send/i (send/i stepper-frame stepper-frame<%> get-widget) widget<%>
                                 add-deriv deriv)))))
 
     (define/public (new-stepper [flags '()])
       (define stepper-frame (new-stepper-frame))
-      (define stepper (send: stepper-frame stepper-frame<%> get-widget))
+      (define stepper (send/i stepper-frame stepper-frame<%> get-widget))
       (send stepper-frame show #t)
       (add-stepper! stepper-frame flags)
       stepper)
@@ -65,6 +64,6 @@
 
 (define (go stx)
   (define director (new macro-stepper-director%))
-  (define stepper (send: director director<%> new-stepper))
-  (send: director director<%> add-deriv (trace stx))
+  (define stepper (send/i director director<%> new-stepper))
+  (send/i director director<%> add-deriv (trace stx))
   (void))
diff --git a/collects/unstable/find.rkt b/collects/unstable/find.rkt
index 86fdbb2..0ca5a23 100644
--- a/collects/unstable/find.rkt
+++ b/collects/unstable/find.rkt
@@ -70,4 +70,3 @@
     (if (procedure? default)
         (default)
         default)))
-;; Eli: Note that this is documented "Like `find-first'".