diff --git a/collects/mred/panel.ss b/collects/mred/panel.ss
new file mode 100644
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--- /dev/null
+++ b/collects/mred/panel.ss
@@ -0,0 +1,100 @@
+(define mred:panel@
+  (unit/sig mred:panel^
+    (import [mred:debug : mred:debug^]
+	    [mred:container : mred:container^]
+	    [mred:canvas : mred:canvas^]
+	    mzlib:function^)
+
+    (mred:debug:printf 'invoke "mred:panel@")
+
+    (define make-edit-panel%
+      (lambda (super%)
+	(class-asi super%
+	  (rename [super-change-children change-children])
+	  (inherit children get-parent)
+	  (public [get-canvas% (lambda () mred:canvas:editor-canvas%)])
+	  (private
+	    [edit-mapping (make-hash-table)]
+	    [bind
+	     (lambda (panel edit)
+	       (hash-table-put! edit-mapping edit panel))]
+	    [lookup/add
+	     (lambda (child)
+	       (if (is-a? child wx:media-edit%)
+		   (let ([add-new
+			  (lambda ()
+			    (let ([p (make-object (get-canvas%) this)])
+			      (send p set-media child)
+			      (send child add-canvas p)
+			      (bind p child)
+			      p))])
+		     (hash-table-get edit-mapping child add-new))
+		   child))])
+						     
+	  (public
+
+	    ; this contains the edits and panels that are children of
+	    ; this panel, but the canvases of these edits are not
+	    ; necessarily immediate children, since they may be split.
+	    [actual-children null]
+	   
+
+	    [collapse
+	     (lambda (canvas)
+	       (letrec* ([media (send canvas get-media)]
+			 [helper
+			  (lambda (canvas/panel)
+			    (printf "collapse; canvas/panel: ~a~n" canvas/panel)
+			    (let* ([parent (send canvas/panel get-parent)])
+			      (if (is-a? parent wx:frame%)
+				  (begin (send canvas/panel change-children
+					       (lambda (l) (list media)))
+					 (wx:bell))
+				  (let* ([parents-children (ivar parent children)]
+					 [num-children (length parents-children)])
+				    (printf "collapse; parent: ~a num-children: ~a~n" parent num-children)
+				    (if (<= num-children 1)
+					(collapse parent)
+					(begin (send parent delete-child canvas/panel)
+					       (send (car (ivar parent children)) set-focus)))))))])
+		 (send media remove-canvas canvas)
+		 (helper canvas)))]
+
+	    [split
+	     (opt-lambda (canvas [panel% mred:container:horizontal-panel%])
+	       (let ([frame (ivar canvas frame)])
+		 (dynamic-wind
+		  (lambda () (send frame set-perform-updates #f))
+		  (lambda () (letrec* ([media (send canvas get-media)]
+				       [canvas% (object-class canvas)]
+				       [parent (send canvas get-parent)]
+				       [new-panel (make-object panel% parent)]
+				       [left-split (make-object canvas% new-panel)]
+				       [right-split (make-object canvas% new-panel)])
+			       (send parent change-children
+				     (lambda (l)
+				       (let ([before (remq new-panel l)])
+					 (map (lambda (x) (if (eq? x canvas)
+							      new-panel
+							      x))
+					      before))))
+			       (send* media (remove-canvas canvas)
+				            (add-canvas left-split)
+					    (add-canvas right-split))
+			       (send* left-split (set-media media) (set-frame frame) (set-focus))
+			       (send* right-split (set-media media) (set-frame frame))
+			       (when (eq? this parent)
+				 (bind media new-panel))))
+		  (lambda () (send frame set-perform-updates #t)))))]
+	    [change-children
+	     (lambda (f)
+	       (let ([new-children (f actual-children)])
+		 (super-change-children (lambda (l)
+					  (map lookup/add
+					       new-children)))
+		 (set! actual-children new-children)))]))))
+    
+    (define horizontal-edit-panel%
+      (make-edit-panel% mred:container:horizontal-panel%))    
+    (define vertical-edit-panel%
+      (make-edit-panel% mred:container:vertical-panel%))))
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