Index: lisp/gutter-items.el
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/Attic/gutter-items.el,v
retrieving revision 1.1.2.31
diff -u -r1.1.2.31 gutter-items.el
--- lisp/gutter-items.el 2000/02/26 21:28:32 1.1.2.31
+++ lisp/gutter-items.el 2000/02/27 21:10:52
@@ -30,26 +30,13 @@
   "Input from the gutters."
   :group 'environment)
 
-(defvar gutter-buffers-tab nil
-  "A tab widget in the gutter for displaying buffers.
-Do not set this. Use `glyph-image-instance' and
-`set-image-instance-property' to change the properties of the tab.")
-
-(defcustom gutter-visible-p 
-  (specifier-instance default-gutter-visible-p)
-  "Whether the default gutter is globally visible. This option can be
-customized through the options menu."
-  :group 'gutter
-  :type 'boolean
-  :set #'(lambda (var val)
-	   (set-specifier default-gutter-visible-p val)
-	   (setq gutter-visible-p val)
-	   (when gutter-buffers-tab (update-tab-in-gutter))))
-
+;; Although these customizations appear bogus, they are neccessary in
+;; order to be able to save options through the options menu.
 (defcustom default-gutter-position
   (default-gutter-position)
   "The location of the default gutter. It can be 'top, 'bottom, 'left or
-'right. This option can be customized through the options menu."
+'right. This option should be customized through the options menu.
+To set the gutter position explicitly use `set-default-gutter-position'"
   :group 'gutter
   :type '(choice (const :tag "top" top)
 		 (const :tag "bottom" bottom)
@@ -57,59 +44,68 @@
 		 (const :tag "right" right))
   :set #'(lambda (var val)
 	   (set-default-gutter-position val)
-	   (setq default-gutter-position val)
-	   (when gutter-buffers-tab (update-tab-in-gutter))))
+	   (setq default-gutter-position val)))
 
 ;;; Gutter helper functions
 
+;; called by Fset_default_gutter_position()
+(defvar default-gutter-position-changed-hook nil
+  "Function or functions to be called when the gutter position is changed.
+The value of this variable may be buffer-local.")
+
+;; called by set-gutter-element-visible-p
+(defvar gutter-element-visibility-changed-hook nil
+  "Function or functions to be called when the visibility of an
+element in the gutter changes.  The value of this variable may be
+buffer-local. The gutter element symbol is passed as an argument to
+the hook, as is the visibility flag.")
+
 (defun set-gutter-element (gutter-specifier prop val &optional locale tag-set)
   "Set GUTTER-SPECIFIER gutter element PROP to VAL in optional LOCALE.
 This is a convenience function for setting gutter elements."
-  (let ((spec-list (specifier-spec-list gutter-specifier locale tag-set)))
-    (if spec-list
-      (add-spec-list-to-specifier
-       gutter-specifier
-       (mapcar #'(lambda (spec)
-		   (setcdr (car (cdr spec))
-			   (plist-put (cdr (car (cdr spec)))
-				      prop val))
-		   spec) spec-list)
-       'remove-all)
-      (set-specifier gutter-specifier (list prop val) locale tag-set))))
+  (map-extents #'(lambda (extent arg) 
+		   (set-extent-property extent 'duplicable t)) val)
+  (modify-specifier-instances gutter-specifier #'plist-put (list prop val)
+                              'force nil locale tag-set))
 
 (defun remove-gutter-element (gutter-specifier prop &optional locale tag-set)
   "Remove gutter element PROP from GUTTER-SPECIFIER in optional LOCALE.
 This is a convenience function for removing gutter elements."
-  (let ((spec-list (specifier-spec-list gutter-specifier locale tag-set)))
-    (when spec-list
-      (add-spec-list-to-specifier
-       gutter-specifier
-       (mapcar #'(lambda (spec)
-		   (setcdr (car (cdr spec))
-			   (plist-remprop (cdr (car (cdr spec)))
-					  prop))
-		   spec) spec-list)
-       'remove-all))))
+  (modify-specifier-instances gutter-specifier #'plist-remprop (list prop)
+                              'force nil locale tag-set))
 
-(defun set-gutter-element-visible-p (gutter-specifier 
+(defun set-gutter-element-visible-p (gutter-visible-specifier-p
 				     prop &optional visible-p
 				     locale tag-set)
-  "Make gutter element PROP VISIBLE-P for GUTTER-SPECIFIER in optional LOCALE.
+  "Change the visibility of gutter elements.
+Set the visibility of element PROP to VISIBLE-P for
+GUTTER-SPECIFIER-VISIBLE-P in optional LOCALE.  
 This is a convenience function for hiding and showing gutter elements."
-  (let ((spec-list (specifier-spec-list gutter-specifier locale tag-set)))
-    (cond (spec-list
-	   (add-spec-list-to-specifier
-	    gutter-specifier
-	    (mapcar #'(lambda (spec)
-			(setcdr (car (cdr spec))
-				(if visible-p
-				    (cons prop (cdr (car (cdr spec))))
-				  (delq prop (cdr (car (cdr spec))))))
-			spec) spec-list)
-	    'remove-all))
-	  (visible-p
-	   (set-specifier gutter-specifier (list prop) locale tag-set))
-	  (t nil))))
+  (modify-specifier-instances 
+   gutter-visible-specifier-p #'(lambda (spec prop visible-p)
+				  (if (consp spec)
+				      (if visible-p 
+					  (if (memq prop spec) spec  
+					    (cons prop spec))
+					(delq prop spec))
+				    (if visible-p (list prop))))
+   (list prop visible-p)
+   'force nil locale tag-set)
+  (run-hook-with-args 'gutter-element-visibility-changed-hook prop visible-p))
+
+(defun gutter-element-visible-p (gutter-visible-specifier-p
+				 prop &optional domain)
+  "Determine whether a gutter element is visible.
+Given GUTTER-VISIBLE-SPECIFIER-P and gutter element PROP, return
+non-nil if it is visible in optional DOMAIN."
+  (let ((spec (specifier-instance gutter-visible-specifier-p domain)))
+    (or (and (listp spec) (memq 'buffers-tab spec))
+ 	spec)))
+
+(defun init-gutter ()
+  "Initialize the gutter."
+  ;; do nothing as yet.
+  )
 
 ;;; The Buffers tab
 
@@ -117,6 +113,21 @@
   "Customization of `Buffers' tab."
   :group 'gutter)
 
+(defvar gutter-buffers-tab nil
+  "A tab widget in the gutter for displaying buffers.
+Do not set this. Use `glyph-image-instance' and
+`set-image-instance-property' to change the properties of the tab.")
+
+(defcustom gutter-buffers-tab-visible-p
+  (gutter-element-visible-p default-gutter-visible-p 'buffers-tab)
+  "Whether the buffers tab is globally visible. 
+This option should be set through the options menu."
+  :group 'buffers-tab
+  :type 'boolean
+  :set #'(lambda (var val)
+	   (set-gutter-element-visible-p default-gutter-visible-p 'buffers-tab val)
+	   (setq gutter-buffers-tab-visible-p val)))
+
 (defvar gutter-buffers-tab-orientation 'top
   "Where the buffers tab currently is. Do not set this.")
 
@@ -293,9 +304,9 @@
 (defun add-tab-to-gutter ()
   "Put a tab control in the gutter area to hold the most recent buffers."
   (setq gutter-buffers-tab-orientation (default-gutter-position))
-  (let ((gutter-string ""))
+  (let ((gutter-string "\n"))
     (unless gutter-buffers-tab-extent
-      (setq gutter-buffers-tab-extent (make-extent 0 0 gutter-string)))
+      (setq gutter-buffers-tab-extent (make-extent 0 1 gutter-string)))
     (set-extent-begin-glyph 
      gutter-buffers-tab-extent
      (setq gutter-buffers-tab 
@@ -309,28 +320,32 @@
 			    (eq gutter-buffers-tab-orientation 'bottom))
 			'(gutter-pixel-width) '(gutter-pixel-height))
 		    :properties (list :items (buffers-tab-items))))))
-    ;; This looks better than a 3d border
+
+    ;; Nuke all existing tabs
+    (remove-gutter-element top-gutter 'buffers-tab)
+    (remove-gutter-element bottom-gutter 'buffers-tab)
+    (remove-gutter-element left-gutter 'buffers-tab)
+    (remove-gutter-element right-gutter 'buffers-tab)
+    ;; Put tabs into all devices that will be able to display them
     (mapcar
      #'(lambda (x)
 	 (when (valid-image-instantiator-format-p 'tab-control x)
-	   (set-specifier default-gutter-border-width 0 'global x)
-	   (set-specifier top-gutter nil 'global x)
-	   (set-specifier bottom-gutter nil 'global x)
-	   (set-specifier left-gutter nil 'global x)
-	   (set-specifier right-gutter nil 'global x)
-	   (set-specifier left-gutter-width 0 'global x)
-	   (set-specifier right-gutter-width 0 'global x)
 	   (cond ((eq gutter-buffers-tab-orientation 'top)
-		  (set-specifier top-gutter gutter-string 'global x))
+		  ;; This looks better than a 3d border
+		  (set-specifier top-gutter-border-width 0 'global x)
+		  (set-gutter-element top-gutter 'buffers-tab gutter-string 'global x))
 		 ((eq gutter-buffers-tab-orientation 'bottom)
-		  (set-specifier bottom-gutter gutter-string 'global x))
+		  (set-specifier bottom-gutter-border-width 0 'global x)
+		  (set-gutter-element bottom-gutter 'buffers-tab gutter-string 'global x))
 		 ((eq gutter-buffers-tab-orientation 'left)
-		  (set-specifier left-gutter gutter-string 'global x)
+		  (set-specifier left-gutter-border-width 0 'global x)
+		  (set-gutter-element left-gutter 'buffers-tab gutter-string 'global x)
 		  (set-specifier left-gutter-width
 				 (glyph-width gutter-buffers-tab)
 				 'global x))
 		 ((eq gutter-buffers-tab-orientation 'right)
-		  (set-specifier right-gutter gutter-string 'global x)
+		  (set-specifier right-gutter-border-width 0 'global x)
+		  (set-gutter-element right-gutter 'buffers-tab gutter-string 'global x)
 		  (set-specifier right-gutter-width
 				 (glyph-width gutter-buffers-tab)
 				 'global x))
@@ -366,9 +381,18 @@
 			(get-buffer-create "*scratch*")))))
       (set-image-instance-property inst :items buffers))))
 
+(defun update-tab-hook (&optional arg)
+  (when gutter-buffers-tab (update-tab-in-gutter arg)))
+
 (add-hook 'kill-buffer-hook 'remove-buffer-from-gutter-tab)
-(add-hook 'create-frame-hook 'update-tab-in-gutter)
+(add-hook 'create-frame-hook 'update-tab-hook)
 (add-hook 'record-buffer-hook 'update-tab-in-gutter)
+(add-hook 'default-gutter-position-changed  'update-tab-hook)
+(add-hook 'gutter-element-visibility-changed-hook
+	  #'(lambda (prop visible-p)
+	      (when (and (eq prop 'buffers-tab)
+			 visible-p)
+		(update-tab-in-gutter))))
 
 ;;
 ;; progress display
@@ -430,7 +454,7 @@
 				 :pixel-height progress-glyph-height
 				 :orientation 'horizontal))))))
 
-(defvar progress-extent-text "")
+(defvar progress-extent-text "\n")
 (defvar progress-extent nil)
 
 (defun progress-displayed-p (&optional return-string frame)
@@ -469,7 +493,7 @@
 	  oldmsg)
       ;; nothing to display so get rid of the gauge
       (set-specifier bottom-gutter-border-width 0 frame)
-      (set-specifier bottom-gutter-visible-p nil frame))))
+      (set-gutter-element-visible-p bottom-gutter-visible-p 'progress nil frame))))
 
 (defun remove-progress (&optional label frame)
   ;; If label is nil, we want to remove all matching progress gauges.
@@ -526,16 +550,16 @@
 		(redisplay-echo-area)))
 	;; do some funky display here.
 	(unless progress-extent
-	  (setq progress-extent (make-extent 0 0 progress-extent-text)))
+	  (setq progress-extent (make-extent 0 1 progress-extent-text)))
 	(let ((bglyph (extent-begin-glyph progress-extent)))
 	  (set-extent-begin-glyph progress-extent progress-abort-glyph)
 	  ;; fixup the gutter specifiers
-	  (set-specifier bottom-gutter progress-extent-text frame)
+	  (set-gutter-element bottom-gutter 'progress progress-extent-text frame)
 	  (set-specifier bottom-gutter-border-width 2 frame)
 	  (set-image-instance-property 
 	   (glyph-image-instance progress-text-glyph) :data message)
 	  (set-specifier bottom-gutter-height 'autodetect frame)
-	  (set-specifier bottom-gutter-visible-p t frame)
+	  (set-gutter-element-visible-p bottom-gutter-visible-p 'progress t frame)
 	  ;; we have to do this so redisplay is up-to-date and so
 	  ;; redisplay-gutter-area performs optimally.
 	  (redisplay-gutter-area)
@@ -561,10 +585,10 @@
 		(redisplay-echo-area)))
 	;; do some funky display here.
 	(unless progress-extent
-	  (setq progress-extent (make-extent 0 0 progress-extent-text))
+	  (setq progress-extent (make-extent 0 1 progress-extent-text))
 	  (set-extent-begin-glyph progress-extent progress-layout-glyph))
 	;; fixup the gutter specifiers
-	(set-specifier bottom-gutter progress-extent-text frame)
+	(set-gutter-element bottom-gutter 'progress progress-extent-text frame)
 	(set-specifier bottom-gutter-border-width 2 frame)
 	(set-image-instance-property 
 	 (glyph-image-instance progress-gauge-glyph) :percent val)
@@ -572,7 +596,7 @@
 	 (glyph-image-instance progress-text-glyph) :data message)
 	(if (and (eq (specifier-instance bottom-gutter-height frame)
 		     'autodetect)
-		 (specifier-instance bottom-gutter-visible-p frame))
+		 (gutter-element-visible-p bottom-gutter-visible-p 'progress frame))
 	    (progn
 	      ;; if the gauge is already visible then just draw the gutter
 	      ;; checking for user events
@@ -581,7 +605,7 @@
 		(dispatch-event (next-command-event))))
 	  ;; otherwise make the gutter visible and redraw the frame
 	  (set-specifier bottom-gutter-height 'autodetect frame)
-	  (set-specifier bottom-gutter-visible-p t frame)
+	  (set-gutter-element-visible-p bottom-gutter-visible-p 'progress t frame)
 	  ;; we have to do this so redisplay is up-to-date and so
 	  ;; redisplay-gutter-area performs optimally.
 	  (redisplay-frame)
Index: lisp/menubar-items.el
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/menubar-items.el,v
retrieving revision 1.6.2.18
diff -u -r1.6.2.18 menubar-items.el
--- lisp/menubar-items.el 2000/01/26 12:33:55 1.6.2.18
+++ lisp/menubar-items.el 2000/02/27 21:10:57
@@ -739,11 +739,11 @@
 	       )))
       ,@(if (featurep 'gutter)
 	    '(("Gutter Appearance"
-	       ["Visible"
-		(customize-set-variable 'gutter-visible-p
-					(not gutter-visible-p))
+	       ["Buffers Tab Visible"
+		(customize-set-variable 'gutter-buffers-tab-visible-p
+					(not gutter-buffers-tab-visible-p))
 		:style toggle
-		:selected gutter-visible-p]
+		:selected gutter-buffers-tab-visible-p]
 	       ("Default Location"
 		["Top"
 		 (customize-set-variable 'default-gutter-position 'top)
Index: lisp/msw-init.el
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/msw-init.el,v
retrieving revision 1.7
diff -u -r1.7 msw-init.el
--- lisp/msw-init.el 1998/06/02 03:50:19 1.7
+++ lisp/msw-init.el 2000/02/27 21:10:57
@@ -47,6 +47,7 @@
 	(if (featurep 'infodock)
 	    (require 'id-x-toolbar)
 	  (init-x-toolbar)))
+    (if (featurep 'gutter) (init-gutter))
     (add-hook 'zmacs-deactivate-region-hook
 	      (lambda ()
 		(if (console-on-window-system-p)
Index: lisp/specifier.el
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/specifier.el,v
retrieving revision 1.8
diff -u -r1.8 specifier.el
--- lisp/specifier.el 1998/06/30 06:35:26 1.8
+++ lisp/specifier.el 2000/02/27 21:11:00
@@ -403,6 +403,40 @@
 	    how-to-add))))
   value)
 
+(defun modify-specifier-instances (specifier func &optional args force default
+					     locale tag-set)
+  "Modify all specifications that match LOCALE and TAG-SET by FUNC.
+
+For each specification that exists for SPECIFIER, in locale LOCALE
+that matches TAG-SET, call the function FUNC with the instance as its
+first argument and with optional arguments ARGS.  The result is then
+used as the new value of the instantiator.
+
+If there is no specification in the domain LOCALE matching TAG-SET and
+FORCE is non-nil, an explicit one is created from the matching
+specifier instance if that exists or DEFAULT otherwise. If LOCALE is
+not a domain (i.e. a buffer), DEFAULT is always used. FUNC is then
+applied like above and the resulting specification is added."
+
+  (let ((spec-list (specifier-spec-list specifier locale tag-set)))
+    (cond
+     (spec-list
+      ;; Destructively edit the spec-list
+      (mapc #'(lambda (spec)
+		(mapc #'(lambda (inst-pair)
+			  (setcdr inst-pair
+				  (apply func (cdr inst-pair) args)))
+		      (cdr spec)))
+	    spec-list)
+      (add-spec-list-to-specifier specifier spec-list))
+     (force
+      (set-specifier specifier
+                     (apply func
+                            (or (and (valid-specifier-domain-p locale)
+                                     (specifier-instance specifier))
+                                default) args)
+                     locale tag-set)))))
+
 (defmacro let-specifier (specifier-list &rest body)
   "Add specifier specs, evaluate forms in BODY and restore the specifiers.
 \(let-specifier SPECIFIER-LIST BODY...)
Index: lisp/x-init.el
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/x-init.el,v
retrieving revision 1.8.2.2
diff -u -r1.8.2.2 x-init.el
--- lisp/x-init.el 1998/12/05 16:54:55 1.8.2.2
+++ lisp/x-init.el 2000/02/27 21:11:02
@@ -305,8 +305,8 @@
         (init-x-toolbar))
     (if (and (featurep 'infodock) (featurep 'toolbar))
 	(require 'id-x-toolbar))
-    (if (featurep 'mule)
-        (init-mule-x-win))
+    (if (featurep 'gutter) (init-gutter))
+    (if (featurep 'mule) (init-mule-x-win))
     ;; these are only ever called if zmacs-regions is true.
     (add-hook 'zmacs-deactivate-region-hook
 	      (lambda ()
Index: src/gutter.c
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/src/Attic/gutter.c,v
retrieving revision 1.1.2.20
diff -u -r1.1.2.20 gutter.c
--- src/gutter.c 2000/02/26 21:26:11 1.1.2.20
+++ src/gutter.c 2000/02/27 21:11:14
@@ -48,6 +48,7 @@
 
 Lisp_Object Qgutter_size;
 Lisp_Object Qgutter_visible;
+Lisp_Object Qdefault_gutter_position_changed_hook;
 
 #define SET_GUTTER_WAS_VISIBLE_FLAG(frame, pos, flag)	\
   do {							\
@@ -514,14 +515,21 @@
 			      list1 (Fcons (Qnil, Qzero)));
       set_specifier_fallback (Vgutter_border_width[new],
 			      Vdefault_gutter_border_width);
+      /* We don't realy want the left and right gutters to default to
+         visible. */
       set_specifier_fallback (Vgutter_visible_p[cur],
-			      list1 (Fcons (Qnil, Qt)));
+			      cur == TOP_GUTTER || cur == BOTTOM_GUTTER ?
+			      list1 (Fcons (Qnil, Qt))
+			      : list1 (Fcons (Qnil, Qnil)));
       set_specifier_fallback (Vgutter_visible_p[new],
 			      Vdefault_gutter_visible_p);
+
       Vdefault_gutter_position = position;
       unhold_frame_size_changes ();
     }
 
+  run_hook (Qdefault_gutter_position_changed_hook);
+  
   return position;
 }
 
@@ -858,6 +866,8 @@
 
   defsymbol (&Qgutter_size, "gutter-size");
   defsymbol (&Qgutter_visible, "gutter-visible");
+  defsymbol (&Qdefault_gutter_position_changed_hook, 
+	     "default-gutter-position-changed");
 }
 
 void