diff --git a/collects/drscheme/private/language-configuration.ss b/collects/drscheme/private/language-configuration.ss
index a93bf11bcb..00ad0e596f 100644
--- a/collects/drscheme/private/language-configuration.ss
+++ b/collects/drscheme/private/language-configuration.ss
@@ -6,6 +6,7 @@
            mzlib/contract
            mzlib/kw
            mzlib/string
+           mzlib/struct
            "drsig.ss"
            string-constants
            mred
@@ -1308,6 +1309,66 @@
                 [else `(expand ',res)]))))
         (super-instantiate ())))
     
+    (define-struct (simple-settings+assume drscheme:language:simple-settings) (no-redef?))
+    (define simple-settings+assume->vector (make-->vector simple-settings+assume))
+
+    (define (assume-mixin %)
+      (class %
+        (define/override (default-settings) 
+          (extend-simple-settings (super default-settings) #t))
+
+        (define/override (marshall-settings settings)
+          (simple-settings+assume->vector settings))
+
+        (define/override (unmarshall-settings printable)
+          (and (vector? printable)
+               (= (vector-length printable) 7)
+               (let ([base
+                      (super unmarshall-settings
+                             (list->vector
+                              (reverse
+                               (cdr (reverse (vector->list printable))))))])
+                 (and base
+                      (extend-simple-settings
+                       base
+                       (and (vector-ref printable 6) #t))))))
+
+        (define/override (config-panel parent)
+          (let ([p (new vertical-panel% [parent parent])])
+            (let ([base-config (super config-panel p)]
+                  [assume-cb (new check-box%
+                                  [parent 
+                                   (new group-box-panel%
+                                        [parent p]
+                                        [label "Initial Bindings"]
+                                        [stretchable-height #f]
+                                        [stretchable-width #f])]
+                                  [label "Assume initial bindings never change"])])
+              (case-lambda
+               [() (extend-simple-settings (base-config)
+                                           (send assume-cb get-value))]
+               [(c)
+                (base-config c)
+                (send assume-cb set-value (simple-settings+assume-no-redef? c))]))))
+
+        (define/override (default-settings? x)
+          (equal? (simple-settings+assume->vector x)
+                  (simple-settings+assume->vector (default-settings))))
+
+        (define/private (extend-simple-settings s no-redef?)
+          (make-simple-settings+assume (drscheme:language:simple-settings-case-sensitive s)
+                                       (drscheme:language:simple-settings-printing-style s)
+                                       (drscheme:language:simple-settings-fraction-style s)
+                                       (drscheme:language:simple-settings-show-sharing s)
+                                       (drscheme:language:simple-settings-insert-newlines s)
+                                       (drscheme:language:simple-settings-annotations s)
+                                       no-redef?))
+
+        (define/override (use-namespace-require/copy-from-setting? s)
+          (not (simple-settings+assume-no-redef? s)))
+
+        (super-new)))
+
     (define (r5rs-mixin %)
       (class %
         (define/override (on-execute setting run-in-user-thread)
@@ -1317,12 +1378,13 @@
              (read-square-bracket-as-paren #f)
              (read-curly-brace-as-paren #f)
              (read-accept-infix-dot #f)
-             (print-pair-curly-braces #t)
              (print-mpair-curly-braces #f)
              (print-vector-length #f))))
         (define/override (get-transformer-module) #f)
+
         (define/override (default-settings) 
-          (drscheme:language:make-simple-settings #f 'write 'mixed-fraction-e #f #t 'debug))
+          (make-simple-settings+assume #f 'write 'mixed-fraction-e #f #t 'debug #t))
+
         (define/override (order-manuals x)
           (values 
            (list #"r5rs" #"drscheme" #"tour" #"help")
@@ -1344,8 +1406,8 @@
                 (λ (%)
                   (class* % (drscheme:language:language<%>)
                     (define/override (get-one-line-summary) one-line-summary)
-                    (define/override (use-namespace-require/copy?) #t)
-                    (inherit get-module get-transformer-module get-init-code)
+                    (inherit get-module get-transformer-module get-init-code
+                             use-namespace-require/copy-from-setting?)
                     (define/augment (capability-value key)
                       (cond
                         [(eq? key 'drscheme:autocomplete-words) 
@@ -1369,7 +1431,7 @@
                            (get-transformer-module)
                            (get-init-code setting)
                            mred-launcher?
-                           (use-namespace-require/copy?)))))
+                           (use-namespace-require/copy-from-setting? setting)))))
                     (super-new))))]
              [make-simple
               (λ (module id position numbers mred-launcher? one-line-summary extra-mixin)
@@ -1393,7 +1455,7 @@
                       (list -1000 3)
                       #t
                       (string-constant pretty-big-scheme-one-line-summary)
-                      (λ (x) x)))
+                      assume-mixin))
         (add-language
          (make-simple '(lib "r5rs/lang.ss")
                       "plt:r5rs"
@@ -1402,7 +1464,7 @@
                       (list -1000 -1000)
                       #f
                       (string-constant r5rs-one-line-summary)
-                      r5rs-mixin))
+                      (lambda (%) (r5rs-mixin (assume-mixin %)))))
         
         (add-language
          (make-simple 'mzscheme
diff --git a/collects/drscheme/private/language.ss b/collects/drscheme/private/language.ss
index 2284b9a14e..1855a5eb9e 100644
--- a/collects/drscheme/private/language.ss
+++ b/collects/drscheme/private/language.ss
@@ -79,6 +79,7 @@
       get-module
       get-transformer-module
       use-namespace-require/copy?
+      use-namespace-require/copy-from-setting?
       config-panel
       
       get-reader
@@ -167,6 +168,8 @@
     (mixin (simple-module-based-language<%>) (module-based-language<%>)
       (define/public (get-transformer-module) 'mzscheme)
       (define/public (use-namespace-require/copy?) #f)
+      (define/public (use-namespace-require/copy-from-setting? setting)
+        (use-namespace-require/copy?))
       (define/public (use-mred-launcher) #t)
       
       (inherit get-module)
@@ -520,7 +523,7 @@
   ;; given a module-based-language, implements a language
   (define module-based-language->language-mixin
     (mixin (module-based-language<%>) (language<%>)
-      (inherit get-module get-transformer-module use-namespace-require/copy?
+      (inherit get-module get-transformer-module use-namespace-require/copy-from-setting?
                get-init-code use-mred-launcher get-reader)
       
       (define/pubment (capability-value s) 
@@ -539,7 +542,7 @@
       (define/public (get-style-delta) #f)
       (define/override (on-execute setting run-in-user-thread)
         (super on-execute setting run-in-user-thread)
-        (initialize-module-based-language (use-namespace-require/copy?)
+        (initialize-module-based-language (use-namespace-require/copy-from-setting? setting)
                                           (get-module)
                                           (get-transformer-module)
                                           run-in-user-thread))
@@ -554,7 +557,7 @@
                                                  (get-transformer-module)
                                                  (get-init-code setting)
                                                  (use-mred-launcher)
-                                                 (use-namespace-require/copy?)))
+                                                 (use-namespace-require/copy-from-setting? setting)))
       (define/public (extra-repl-information _1 _2) (void))
       (define/public (get-reader-module) #f)
       (define/public (get-metadata a b c) #f)
@@ -1125,12 +1128,9 @@
                         (λ (x)
                           (display (exn-message x))
                           (newline))])
-         (namespace-require module-spec)
-         ;; we always do a require to get the provide-for-syntax bindings
-         ;; if copy semantics is wanted, we do a copy next to clobber (some of)
-         ;; the bindings
-         (when use-copy?
-           (namespace-require/copy module-spec))
+         (if use-copy?
+             (namespace-require/copy module-spec)
+             (namespace-require module-spec))
          (when transformer-module-spec
            (namespace-require `(for-syntax ,transformer-module-spec)))))))
   
diff --git a/collects/drscheme/private/rep.ss b/collects/drscheme/private/rep.ss
index 2e18cde47b..e6ab8a72b5 100644
--- a/collects/drscheme/private/rep.ss
+++ b/collects/drscheme/private/rep.ss
@@ -1052,6 +1052,9 @@ TODO
                         (equal? code #\return)
                         (equal? code #\newline)))
                (super on-local-char key)]
+              [(not prompt-position) 
+               ;; evaluating? just drop the keypress
+               (void)] 
               [(and (< end prompt-position)
                     (= start end)
                     (get-backward-sexp end))
diff --git a/collects/mzlib/pconvert.ss b/collects/mzlib/pconvert.ss
index 24de787093..bf29dee7b5 100644
--- a/collects/mzlib/pconvert.ss
+++ b/collects/mzlib/pconvert.ss
@@ -3,6 +3,7 @@
   
   (require (only "string.ss" expr->string)
            (only "list.ss" sort)
+           scheme/mpair
 	   "etc.ss"
 	   "pconvert-prop.ss"
            "class.ss")
@@ -145,6 +146,10 @@
                     (unless (build-sub expr)
                       (build (car expr))
                       (build (cdr expr)))]
+                   [(mpair? expr)  
+                    (unless (build-sub expr)
+                      (build (mcar expr))
+                      (build (mcdr expr)))]
                    [(vector? expr) 
                     (unless (build-sub expr)
                       (for-each build (vector->list expr)))]
@@ -171,7 +176,8 @@
   (define print-convert-expr
     (lambda (csi expr unroll-once?)
       (letrec
-          ([share-hash (convert-share-info-share-hash csi)]
+          ([mpair-mode? (is-mpair-mode?)]
+           [share-hash (convert-share-info-share-hash csi)]
            [find-hash
             (lambda (expr)
               (hash-table-get share-hash expr (lambda () #f)))]
@@ -209,18 +215,23 @@
            [use-quasi-quote? (not (constructor-style-printing))]
            [use-read-syntax (quasi-read-style-printing)]
            [doesnt-contain-shared-conses
-            (lambda (input-expr)
-              (letrec ([doesnt-contain-shared-conses
-                        (lambda (expr)
-                          (cond
-                            [(and (pair? expr)
-                                  (shared? expr))
-                             #f]
-                            [(pair? expr)
-                             (doesnt-contain-shared-conses (cdr expr))]
-                            [else #t]))])
-                (let ([answer (doesnt-contain-shared-conses input-expr)])
-                  answer)))]
+            (lambda (expr)
+              (cond
+               [(and (pair? expr)
+                     (shared? expr))
+                #f]
+               [(pair? expr)
+                (doesnt-contain-shared-conses (cdr expr))]
+               [else #t]))]
+           [doesnt-contain-shared-mconses
+            (lambda (expr)
+              (cond
+               [(and (mpair? expr)
+                     (shared? expr))
+                #f]
+               [(mpair? expr)
+                (doesnt-contain-shared-mconses (mcdr expr))]
+               [else #t]))]
            [get-whole/frac
             (lambda (exact-num)
               (let ([split 
@@ -252,10 +263,8 @@
                                                          (zero? frac))))))))
                             (and (symbol? expr)
                                  (not (eq? expr 'quasiquote))
-                                 (not (eq? expr 'quote))
                                  (not (eq? expr 'unquote))
-                                 (not (eq? expr 'quote-syntax))
-                                 (not (eq? expr 'syntax)))
+                                 (not (eq? expr 'unquote-splicing)))
                             (char? expr)
                             (string? expr)
                             (not expr)
@@ -270,21 +279,12 @@
                       (lambda ()
                         (cond
                           [(null? expr) '()]
-                          [(and (pair? expr)
-                                (pair? (cdr expr))
-                                (null? (cddr expr))
-                                (or (eq? (car expr) 'quote)
-                                    (eq? expr 'quasiquote)
-                                    (eq? expr 'quote)
-                                    (eq? expr 'unquote)
-                                    (eq? expr 'quote-syntax)
-                                    (eq? expr 'syntax)))
-                           `(,(car expr) ,(recur (cadr expr)))]
-                          [(and (list? expr)
-                                (doesnt-contain-shared-conses expr))
-                           (map recur expr)]
                           [(pair? expr) 
                            (cons (recur (car expr)) (recur (cdr expr)))]
+                          [(and mpair-mode?
+                                (mpair? expr))
+                           ;; generate pairs, which will be converted back to mpairs later
+                           (cons (recur (mcar expr)) (recur (mcdr expr)))]
                           [(self-quoting? expr) expr]
                           [else `(,'unquote ,((print #f first-time) expr))]))]
                      
@@ -335,6 +335,21 @@
                                 (guard/quasiquote
                                  (lambda ()
                                    `(cons ,(recur (car expr)) ,(recur (cdr expr)))))]
+                               [(and mpair-mode?
+                                     (abbreviate-cons-as-list)
+                                     (mlist? expr)
+                                     (or (and first-time
+                                              (doesnt-contain-shared-mconses (mcdr expr)))
+                                         (doesnt-contain-shared-mconses expr)))
+                                (guard/quasiquote
+                                 (lambda ()
+                                   `(list ,@(map recur (mlist->list expr)))))]
+                               [(mpair? expr)
+                                (if mpair-mode?
+                                    (guard/quasiquote
+                                     (lambda ()
+                                       `(cons ,(recur (mcar expr)) ,(recur (mcdr expr)))))
+                                    `(mcons ,(recur (mcar expr)) ,(recur (mcdr expr))))]
                                [(weak-box? expr) `(make-weak-box ,(recur (weak-box-value expr)))]
                                [(box? expr) `(box ,(recur (unbox expr)))]
                                [(hash-table? expr) `(,(cond
@@ -448,6 +463,9 @@
                                 (quasi-style))
                             (constructor-style)))))))])
         ((print #f unroll-once?) expr))))
+
+  (define (is-mpair-mode?)
+    (not (print-mpair-curly-braces)))
   
   ;; type (improper-list a) = (union (cons (improper-list a) (improper-list a)) null a)
   ;; improper-map : (a -> b) -> (improper-list a) -> (improper-list b)
diff --git a/collects/mzlib/scribblings/pconvert.scrbl b/collects/mzlib/scribblings/pconvert.scrbl
index f74855958c..b47ac74fb2 100644
--- a/collects/mzlib/scribblings/pconvert.scrbl
+++ b/collects/mzlib/scribblings/pconvert.scrbl
@@ -86,6 +86,13 @@ used; e.g., the pair containing @scheme[1] and @scheme[2] is
 represented as @scheme[`(1 . 2)]. The initial value of the parameter
 is @scheme[#f].
 
+The constructor used for mutable pairs is @schemeidfont{mcons}, unless
+@scheme[print-mpair-curly-braces] is set to @scheme[#f], in which case
+@schemeidfont{cons} and @schemeidfont{list} are used. Similarly, when
+using @scheme[quasiquote] style and @scheme[print-mpair-curly-braces]
+is set to @scheme[#f], mutable pair constructions are represented
+using @schemeidfont{quote}, @schemeidfont{quasiquote}, etc.
+
 See also @scheme[quasi-read-style-printing] and
 @scheme[prop:print-convert-constructor-name].}
 
diff --git a/collects/scheme/mpair.ss b/collects/scheme/mpair.ss
index 6e14373100..5fbb9d118e 100644
--- a/collects/scheme/mpair.ss
+++ b/collects/scheme/mpair.ss
@@ -96,9 +96,22 @@
 (define (mlist? l)
   (cond
    [(null? l) #t]
-   [(mpair? l) (mlist? (mcdr l))]
+   [(mpair? l)
+    (let loop ([turtle l][hare (mcdr l)])
+      (cond
+       [(null? hare) #t]
+       [(eq? hare turtle) #f]
+       [(mpair? hare)
+        (let ([hare (mcdr hare)])
+          (cond
+           [(null? hare) #t]
+           [(eq? hare turtle) #f]
+           [(mpair? hare)
+            (loop (mcdr turtle) (mcdr hare))]
+           [else #f]))]
+       [else #f]))]
    [else #f]))
-
+  
 (define (mlength l)
   (let loop ([l l][len 0])
     (cond
diff --git a/collects/scribblings/reference/reader.scrbl b/collects/scribblings/reference/reader.scrbl
index 0175ab3390..22039a26f9 100644
--- a/collects/scribblings/reference/reader.scrbl
+++ b/collects/scribblings/reference/reader.scrbl
@@ -364,11 +364,11 @@ then when then reader encounters @litchar["{"] and @litchar["}"], the
 @exnraise{exn:fail:read}.
 
 If the @scheme[read-accept-dot] @tech{parameter} is set to
-@scheme[#f], then a delimited @scheme{.} is not treated specially; it
-is instead parsed as a symbol. If the @scheme[read-accept-infix-dot]
-@tech{parameter} is set to @scheme[#f], then multiple delimited
-@litchar{.}s trigger a @scheme[exn:fail:read], instead of the infix
-conversion.
+@scheme[#f], then a delimited @litchar{.} triggers an
+@scheme[exn:fail:read] exception. If the
+@scheme[read-accept-infix-dot] @tech{parameter} is set to @scheme[#f],
+then multiple delimited @litchar{.}s trigger an @scheme[exn:fail:read]
+exception, instead of the infix conversion.
 
 @section[#:tag "parse-string"]{Reading Strings}
 
diff --git a/collects/tests/drscheme/io.ss b/collects/tests/drscheme/io.ss
index 09a4ad99ec..456c268fa7 100644
--- a/collects/tests/drscheme/io.ss
+++ b/collects/tests/drscheme/io.ss
@@ -185,7 +185,7 @@ add this test:
   
   (define drs-frame (wait-for-drscheme-frame))
   (define interactions-text (send drs-frame get-interactions-text))
-  (set-language-level! (list "PLT" (regexp "Textual")))
+  (set-language-level! (list "Pretty Big (includes MrEd and Advanced Student)"))
   
   (define (run-test)
     (output-err-port-checking) ;; must come first
diff --git a/collects/tests/drscheme/language-test.ss b/collects/tests/drscheme/language-test.ss
index 501483c64d..68adf4b9e3 100644
--- a/collects/tests/drscheme/language-test.ss
+++ b/collects/tests/drscheme/language-test.ss
@@ -41,6 +41,7 @@ the settings above should match r5rs
 ;; ; ;; ;;;;    ;;;    ;;; ;
   
 
+  #:
   (define (mred)
     (parameterize ([language (list "PLT" (regexp "Graphical"))])
       (check-top-of-repl)
@@ -61,7 +62,7 @@ the settings above should match r5rs
       
       (test-expression 'xml "(a () (b ()))")
 
-      (test-expression "(define-struct spider (legs))(make-spider 4)" "#<struct:spider>")
+      (test-expression "(define-struct spider (legs))(make-spider 4)" "#<spider>")
       
       (test-expression "(sqrt -1)" "0+1i")
 
@@ -75,7 +76,7 @@ the settings above should match r5rs
       (test-expression "(define (f car) 1)" "")
       (test-expression "(define (f empty) 1)" "")
       
-      (test-expression "call/cc" "#<primitive:call-with-current-continuation>")
+      (test-expression "call/cc" "#<procedure:call-with-current-continuation>")
       
       (test-expression "(error 'a \"~a\" 1)" "{bug09.png} a: 1")
       (test-expression "(error \"a\" \"a\")" "{bug09.png} a \"a\"")
@@ -139,11 +140,9 @@ the settings above should match r5rs
 ;; ; ;; ;;;;;   ;;;    ;;;  ;;; ;;;  ;;;  ;; ; ;;  ;;;  
                                                         
                                                         
-                                                        
-
   
-  (define (mzscheme)
-    (parameterize ([language (list "PLT" (regexp "Textual"))])
+  (define (pretty-big)
+    (parameterize ([language (list "Pretty Big (includes MrEd and Advanced Student)")])
 
       (check-top-of-repl)
 
@@ -160,12 +159,12 @@ the settings above should match r5rs
                        "#f")
       (test-expression "(define x 1)(define x 2)" "")
       
-      (test-expression "(define-struct spider (legs))(make-spider 4)" "#<struct:spider>")
+      (test-expression "(define-struct spider (legs))(make-spider 4)" "#<spider>")
       
       (test-expression "(sqrt -1)" "0+1i")
 
-      (test-expression "class" "{bug09.png} reference to undefined identifier: class")
-      (test-expression "shared" "{bug09.png} reference to undefined identifier: shared")
+      (test-expression "class" (regexp "class: bad syntax in: class"))
+      (test-expression "shared" (regexp "shared: bad syntax in: shared"))
       
       (test-expression "(define (. x y) (* x y))" #rx"read: illegal use of \"\\.\"")
       (test-expression "'(1 . 2)" "(1 . 2)")
@@ -174,7 +173,7 @@ the settings above should match r5rs
       (test-expression "(define (f car) 1)" "")
       (test-expression "(define (f empty) 1)" "")
       
-      (test-expression "call/cc" "#<primitive:call-with-current-continuation>")
+      (test-expression "call/cc" "#<procedure:call-with-current-continuation>")
       
       (test-expression "(error 'a \"~a\" 1)" "{bug09.png} a: 1")
       (test-expression "(error \"a\" \"a\")" "{bug09.png} a \"a\"")
@@ -182,7 +181,7 @@ the settings above should match r5rs
       (test-expression "(time 1)" 
                        #rx"cpu time: [0-9]+ real time: [0-9]+ gc time: [0-9]+\n1")
       
-      (test-expression "true" "{bug09.png} reference to undefined identifier: true")
+      (test-expression "true" "#t")
       (test-expression "mred^" "{bug09.png} reference to undefined identifier: mred^")
       (test-expression "(eq? 'a 'A)" "#f")
       (test-expression "(set! x 1)" "{bug09.png} set!: cannot set undefined identifier: x")
@@ -193,9 +192,7 @@ the settings above should match r5rs
       (test-expression "'(1)" "(1)")
       (test-expression "(define shrd (box 1)) (list shrd shrd)"
                        "(#&1 #&1)")
-      (test-expression 
-       "(local ((define x x)) 1)"
-       #rx"define: not allowed in an expression context")
+      (test-expression "(local ((define x x)) 1)" "1")
       (test-expression "(letrec ([x x]) 1)" "1")
       (test-expression "(if 1 1 1)" "1")
       (test-expression "(+ 1)" "1")
@@ -221,7 +218,7 @@ the settings above should match r5rs
       (test-expression "(list 1)" "(1)")
       (test-expression "(car (list))" "{bug09.png} car: expects argument of type <pair>; given ()")
       
-      (test-expression "argv" "#0()")
+      (test-expression "(current-command-line-arguments)" "#()")
       (test-expression "(define-syntax app syntax-case)" "syntax-case: bad syntax in: syntax-case")))
 
   
@@ -324,7 +321,7 @@ the settings above should match r5rs
 
       (test-expression "(list 1)" "(1)")
       (test-expression "(car (list))"
-                       "{bug09.png} car: expects argument of type <pair>; given ()")
+                       "{bug09.png} mcar: expects argument of type <mutable-pair>; given ()")
 
       (test-expression "argv" "{bug09.png} reference to undefined identifier: argv")
       (test-expression "(define-syntax app syntax-case)" 
@@ -357,7 +354,7 @@ the settings above should match r5rs
       
       (prepare-for-test-expression)
 
-      (test-expression "'|.|" "'|.|")
+      (test-expression "'|.|" "'.")
       (test-expression '("(equal? (list " image ") (list " image "))") 
                        "true")
       
@@ -378,9 +375,8 @@ the settings above should match r5rs
                        "shared: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: shared")
 
-      (test-expression "(define (. x y) (* x y))"
-                       "read: illegal use of \".\"")
-      (test-expression "'(1 . 2)" "read: illegal use of \".\"")
+      (test-expression "(define (. x y) (* x y))" "read: illegal use of \".\"")
+      (test-expression "'(1 . 2)"  "read: illegal use of \".\"")
       
       (test-expression "call/cc"
                        "call/cc: name is not defined, not a parameter, and not a primitive name"
@@ -450,7 +446,9 @@ the settings above should match r5rs
       (test-expression "argv" 
                        "argv: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: argv")
-      (test-expression "(define-syntax app syntax-case)" "")))
+      (test-expression "(define-syntax app syntax-case)"
+                       "define-syntax: name is not defined, not a parameter, and not a primitive name"
+                       "reference to an identifier before its definition: define-syntax")))
   
 
                                                                
@@ -483,7 +481,7 @@ the settings above should match r5rs
       
       (prepare-for-test-expression)
       
-      (test-expression "'|.|" "'|.|")      
+      (test-expression "'|.|" "'.")      
       (test-expression '("(equal? (list " image ") (list " image "))") 
                        "true")
       
@@ -504,8 +502,8 @@ the settings above should match r5rs
                        "shared: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: shared")
 
-      (test-expression "(define (. x y) (* x y))" "read: illegal use of \".\"")
-      (test-expression "'(1 . 2)" "read: illegal use of \".\"")
+      (test-expression "(define (. x y) (* x y))"  "read: illegal use of \".\"")
+      (test-expression "'(1 . 2)"  "read: illegal use of \".\"")
       
       (test-expression "call/cc"
                        "call/cc: name is not defined, not a parameter, and not a primitive name"
@@ -576,7 +574,8 @@ the settings above should match r5rs
                        "reference to an identifier before its definition: argv")
       
       (test-expression "(define-syntax app syntax-case)" 
-                       "define-syntax: name is not defined, not a parameter, and not a primitive name")))
+                       "define-syntax: name is not defined, not a parameter, and not a primitive name"
+                       "reference to an identifier before its definition: define-syntax")))
 
 
                                                                                     
@@ -607,7 +606,7 @@ the settings above should match r5rs
       
       (prepare-for-test-expression)
       
-      (test-expression "'|.|" "'|.|")
+      (test-expression "'|.|" "'.")
       (test-expression '("(equal? (list " image ") (list " image "))") 
                        "true")
       
@@ -628,8 +627,8 @@ the settings above should match r5rs
                        "shared: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: shared")
       
-      (test-expression "(define (. x y) (* x y))" "read: illegal use of \".\"")
-      (test-expression "'(1 . 2)" "read: illegal use of \".\"")
+      (test-expression "(define (. x y) (* x y))"  "read: illegal use of \".\"")
+      (test-expression "'(1 . 2)"  "read: illegal use of \".\"")
       
       (test-expression "call/cc"
                        "call/cc: name is not defined, not a parameter, and not a primitive name"
@@ -690,8 +689,10 @@ the settings above should match r5rs
       (test-expression "argv" 
                        "argv: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: argv")
+      
       (test-expression "(define-syntax app syntax-case)" 
-                       "define-syntax: name is not defined, not a parameter, and not a primitive name")))
+                       "define-syntax: name is not defined, not a parameter, and not a primitive name"
+                       "reference to an identifier before its definition: define-syntax")))
 
 
                                                                       
@@ -723,7 +724,7 @@ the settings above should match r5rs
       
       (prepare-for-test-expression)
       
-      (test-expression "'|.|" "'|.|")
+      (test-expression "'|.|" "'.")
       (test-expression '("(equal? (list " image ") (list " image "))") 
                        "true")
       (test-expression "(define x 1)(define x 2)"
@@ -805,8 +806,10 @@ the settings above should match r5rs
       (test-expression "argv" 
                        "argv: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: argv")
+      
       (test-expression "(define-syntax app syntax-case)" 
-                       "define-syntax: name is not defined, not a parameter, and not a primitive name")))
+                       "define-syntax: name is not defined, not a parameter, and not a primitive name"
+                       "reference to an identifier before its definition: define-syntax")))
   
 
                                                         
@@ -837,7 +840,7 @@ the settings above should match r5rs
       
       (prepare-for-test-expression)
       
-      (test-expression "'|.|" "'|.|")
+      (test-expression "'|.|" "'.")
       (test-expression '("(equal? (list " image ") (list " image "))") 
                        "true")
       (test-expression "(define x 1)(define x 2)"
@@ -856,8 +859,8 @@ the settings above should match r5rs
 
       (test-expression "shared" "shared: found a use of `shared' that does not follow an open parenthesis")
       
-      (test-expression "(define (. x y) (* x y))" "read: illegal use of \".\"")
-      (test-expression "'(1 . 2)" "read: illegal use of \".\"")
+      (test-expression "(define (. x y) (* x y))"  "read: illegal use of \".\"")
+      (test-expression "'(1 . 2)"  "read: illegal use of \".\"")
       
       (test-expression "call/cc" 
                        "call/cc: name is not defined, not a parameter, and not a primitive name"
@@ -918,8 +921,10 @@ the settings above should match r5rs
       (test-expression "argv"
                        "argv: name is not defined, not a parameter, and not a primitive name"
                        "reference to an identifier before its definition: argv")
+      
       (test-expression "(define-syntax app syntax-case)" 
-                       "define-syntax: name is not defined, not a parameter, and not a primitive name")))
+                       "define-syntax: name is not defined, not a parameter, and not a primitive name"
+                       "reference to an identifier before its definition: define-syntax")))
 
                                                  
                                                  
@@ -982,6 +987,8 @@ the settings above should match r5rs
   (define (check-top-of-repl)
     (let ([drs (wait-for-drscheme-frame)])
       (set-language #t)
+      (with-handlers ([exn:fail? void])
+        (fw:test:menu-select "Testing" "Disable tests"))
       (do-execute drs)
       (let* ([interactions (send drs get-interactions-text)]
              [short-lang (car (last-pair (language)))]
@@ -991,13 +998,16 @@ the settings above should match r5rs
              [line0-expect (format "Welcome to DrScheme, version ~a [3m]." (version:version))]
              [line1-expect 
               (if (string? short-lang)
-                  (format "Language: ~a." short-lang)
+                  (format "Language: ~a" short-lang)
                   short-lang)]
              [line0-got (get-line 0)]
              [line1-got (get-line 1)])
         (unless (and (string=? line0-expect line0-got)
                      (if (string? short-lang)
-                         (string=? line1-expect line1-got)
+                         (string=? line1-expect (substring line1-got
+                                                           0
+                                                           (min (string-length line1-expect)
+                                                                (string-length line1-got))))
                          (regexp-match line1-expect line1-got)))
           (printf "expected lines: ~n  ~a~n  ~a~ngot lines:~n  ~a~n  ~a~n" 
                   line0-expect line1-expect
@@ -1166,12 +1176,12 @@ the settings above should match r5rs
                  (cond
                    [(eq? item 'image)
                     (use-get/put-dialog 
-                     (lambda () (fw:test:menu-select "Special" "Insert Image..."))
-                     (simplify-path (build-path (collection-path "icons") "recycle.gif")))]
+                     (lambda () (fw:test:menu-select "Insert" "Insert Image..."))
+                     (simplify-path (build-path (collection-path "icons") "recycle.png")))]
                    [(string? item)
                     (type-in-definitions drs item)]
                    [(eq? item 'xml)
-                    (fw:test:menu-select "Special" "Insert XML Box")
+                    (fw:test:menu-select "Insert" "Insert XML Box")
                     (for-each fw:test:keystroke (string->list "<a><b>"))]
                    [else (error 'handle-insertion "unknown thing to insert ~s" item)]))]
               [check-expectation
@@ -1246,11 +1256,11 @@ the settings above should match r5rs
                       (printf ">> finished ~a\n" (syntax-object->datum #'arg))))]))
   
   (define (run-test)
-    (go mred)
-    (go mzscheme)
+    ;; (go mred)
+    (go r5rs)
+    (go pretty-big)
     (go beginner)
     (go beginner/abbrev)
     (go intermediate)
     (go intermediate/lambda)
-    (go advanced)
-    (go r5rs)))
+    (go advanced)))
diff --git a/collects/tests/mzscheme/param.ss b/collects/tests/mzscheme/param.ss
index 12b13cfe8b..0472ff6520 100644
--- a/collects/tests/mzscheme/param.ss
+++ b/collects/tests/mzscheme/param.ss
@@ -218,9 +218,7 @@
 		(list read-accept-dot
 		      (list #t #f)
 		      '(let ([p (open-input-string "(1 . 2)")])
-			 (if (list? (read p))
-                             (error "ack")
-                             'ok))
+			 (read p))
 		      exn:fail?
 		      #f)
 		(list read-accept-quasiquote
diff --git a/collects/tests/mzscheme/read.ss b/collects/tests/mzscheme/read.ss
index c3799fccaf..e983348101 100644
--- a/collects/tests/mzscheme/read.ss
+++ b/collects/tests/mzscheme/read.ss
@@ -1003,9 +1003,12 @@
 
 (parameterize ([current-readtable (make-readtable (current-readtable) #\. #\a #f)])
   (test '|.| read (open-input-string ".")))
+(parameterize ([current-readtable (make-readtable (current-readtable) #\. #\a #f)]
+               [read-accept-dot #f])
+  (test '|.| read (open-input-string ".")))
 (parameterize ([read-accept-dot #f]
                [current-readtable (make-readtable (current-readtable) #\w #\. #f)])
-  (test '|w| read (open-input-string "w")))
+  (err/rt-test (read (open-input-string "w")) exn:fail:read?))
 (parameterize ([current-readtable (make-readtable (current-readtable) #\w #\. #f)])
   (err/rt-test (read (open-input-string "w")) exn:fail:read?))
 
diff --git a/doc/release-notes/drscheme/HISTORY.txt b/doc/release-notes/drscheme/HISTORY.txt
index 880c9cc44e..57563c0422 100644
--- a/doc/release-notes/drscheme/HISTORY.txt
+++ b/doc/release-notes/drscheme/HISTORY.txt
@@ -2,6 +2,14 @@
         Version 4.0
 ------------------------------
 
+  . renamed "(module ...)" language to "Module"
+
+  . dropped "MzScheme" and "MrEd" as seperate languages;
+    try `#lang scheme/load' with the "Module" language
+
+  . changed the "Pretty Big" and "R5RS" to assume by default
+    that pre-defined names will not be redefined
+
   . renamed the get-special-menu method to get-insert-menu
 
   . drscheme:debug:show-backtrace-window
diff --git a/src/mzscheme/src/module.c b/src/mzscheme/src/module.c
index 8c6d08714e..bd8277fbd2 100644
--- a/src/mzscheme/src/module.c
+++ b/src/mzscheme/src/module.c
@@ -7748,7 +7748,7 @@ void add_single_require(Scheme_Module_Exports *me, /* from module */
   int is_kern, has_context, save_marshal_info = 0;
   Scheme_Object *nominal_modidx, *one_exn, *prnt_iname, *name, *rn, *ename = orig_ename;
   Scheme_Hash_Table *orig_onlys;
-  int k, skip_rename;
+  int k, skip_rename, do_copy_vars;
   
   if (mark_src) {
     /* Check whether there's context for this import (which
@@ -7824,11 +7824,17 @@ void add_single_require(Scheme_Module_Exports *me, /* from module */
                                                to_phase,
                                                1);
 
+      if (copy_vars)
+        do_copy_vars = !orig_env->module && !orig_env->phase && SAME_OBJ(src_phase_index, scheme_make_integer(0)) && (k == -3);
+      else
+        do_copy_vars = 0;
+
       if (can_save_marshal
           && !exns
           && !prefix
           && !orig_ename
-          && (pt->num_provides || pt->reprovide_kernel)) {
+          && (pt->num_provides || pt->reprovide_kernel)
+          && !do_copy_vars) {
         /* Simple "import everything" whose mappings can be shared via the exporting module: */
         if (!pt->src_modidx)
           pt->src_modidx = me->src_modidx;
@@ -7919,9 +7925,7 @@ void add_single_require(Scheme_Module_Exports *me, /* from module */
                data, cki, form, err_src, mark_src, to_phase, src_phase_index, pt->phase_index);
 
           if (!is_kern) {
-            if (copy_vars && (j < var_count) && !orig_env->module 
-                && SAME_OBJ(src_phase_index, scheme_make_integer(0))
-                && !orig_env->phase && !k) {
+            if (do_copy_vars && (j < var_count)) {
               Scheme_Env *menv;
               Scheme_Object *val;
               modidx = scheme_module_resolve(modidx, 1);
@@ -8440,7 +8444,7 @@ void parse_requires(Scheme_Object *form,
                          rn_set, post_ex_rn_set, NULL,
                          exns, onlys, prefix, iname, ename,
                          mark_src, 
-                         unpack_kern, copy_vars && start, 0, can_save_marshal,
+                         unpack_kern, copy_vars, 0, can_save_marshal,
                          all_simple,
                          ck, data,
                          form, err_src, i);
diff --git a/src/mzscheme/src/read.c b/src/mzscheme/src/read.c
index f91dee7a53..bdf439652c 100644
--- a/src/mzscheme/src/read.c
+++ b/src/mzscheme/src/read.c
@@ -3625,8 +3625,7 @@ read_number_or_symbol(int init_ch, int skip_rt, Scheme_Object *port,
 
   if (!quoted_ever && (i == 1) 
       && (readtable_effective_char(params->table, buf[0]) == '.') 
-      && !honu_mode
-      && params->can_read_dot) {
+      && !honu_mode) {
     long xl, xc, xp;
     scheme_tell_all(port, &xl, &xc, &xp);
     scheme_read_err(port, stxsrc, xl, xc, xp,
diff --git a/src/wxmac/src/mac/wx_frame.cc b/src/wxmac/src/mac/wx_frame.cc
index 749b4ce738..2e7dc3dda2 100644
--- a/src/wxmac/src/mac/wx_frame.cc
+++ b/src/wxmac/src/mac/wx_frame.cc
@@ -73,8 +73,8 @@ wxFrame::wxFrame // Constructor (for frame window)
  ) :
  wxbFrame (windowName, wxScreen::gScreenWindow,
 	   x, y, 
-	   (width < 30) ? 30 : width, 
-	   (height < 40) ? 40 : height, style)
+	   (cStyle & wxNO_CAPTION) ? width : ((width < 30) ? 30 : width), 
+	   (cStyle & wxNO_CAPTION) ? height : ((height < 40) ? 40 : height), style)
 {
   int X, Y, theMacX, theMacY, theMacWidth, theMacHeight;
   Rect theBoundsRect;