...

original commit: ad23bf94bb5b9e0c782d1e064f798d59d3af85cb

collects/framework/editor.ss

@@ -209,10 +209,12 @@
           'framework:auto-set-wrap?)))
       (private
         [remove-callback
-         (preferences:add-callback
-          'framework:auto-set-wrap?
-          (lambda (p v)
-            (auto-wrap v)))])))
+	 (preferences:add-callback
+	  'framework:auto-set-wrap?
+	  (let ([autowrap-mixin-pref-callback
+		 (lambda (p v)
+		   (auto-wrap v))])
+	    autowrap-mixin-pref-callback))])))
   
   (define file<%> (interface (-keymap<%>)))
   (define file-mixin

collects/framework/frame.ss

@@ -1016,12 +1016,15 @@
 		    (if v
 			(list rest-panel outer-info-panel)
 			(list rest-panel))))))])
+      (private
+	[memory-cleanup void]) ;; only for PLTers; used with memory-text
       (override
 	[on-close
 	 (lambda ()
 	   (super-on-close)
 	   (unregister-collecting-blit gc-canvas)
-	   (close-panel-callback))])
+	   (close-panel-callback)
+	   (memory-cleanup))])
       
       (public
 	[lock-status-changed
@@ -1083,6 +1086,10 @@
                  [ec (make-object editor-canvas% panel memory-text '(no-hscroll no-vscroll))])
             (determine-width "000000000" ec memory-text)
             (update-text)
+	    (set! memory-cleanup
+		  (lambda ()
+		    (send memory-text remove-canvas ec)
+		    (send ec set-editor #f)))
             (send panel stretchable-width #f))))
       (private
 	[lock-message (make-object message%

collects/framework/prefs.ss

@@ -14,11 +14,15 @@
 					     [(windows) "mred.pre"]
 					     [else ".mred.prefs"])))
   
+  (define-struct callbacks-ht (ht))
+
   (define preferences (make-hash-table))
   (define marshall-unmarshall (make-hash-table))
-  (define callbacks (make-hash-table))    
+  (define callbacks (make-callbacks-ht (make-hash-table)))
   (define defaults (make-hash-table))
   
+  (printf "hash-tables: ~s~n" (list preferences marshall-unmarshall (callbacks-ht-ht callbacks) defaults))
+
   (define-struct un/marshall (marshall unmarshall))
   (define-struct marshalled (data))
   (define-struct pref (value))
@@ -59,19 +63,26 @@
   
   (define get-callbacks
     (lambda (p)
-      (hash-table-get callbacks
+      (hash-table-get (callbacks-ht-ht callbacks)
 		      p
 		      (lambda () null))))
   
   (define add-callback
     (lambda (p callback)
-      (hash-table-put! callbacks p (append (get-callbacks p) (list callback)))
+      (printf "added callback (~s) for ~s~n" callback p)
+      (hash-table-put! (callbacks-ht-ht callbacks) p (append (get-callbacks p) (list callback)))
       (lambda ()
 	(hash-table-put!
-	 callbacks p
-	 (mzlib:function:remove callback
-				(get-callbacks p)
-				eq?)))))
+	 (callbacks-ht-ht callbacks)
+	 p
+	 (let loop ([callbacks (get-callbacks p)])
+	   (cond
+	    [(null? callbacks) null]
+	    [else (if (eq? (car callbacks) callback)
+		      (begin
+			(printf "removed callback (~s) for ~s~n" callback p)
+			(loop (cdr callbacks)))
+		      (cons (car callbacks) (loop (cdr callbacks))))]))))))
   
   (define check-callbacks
     (lambda (p value)