Bugfixes for `customize-create-theme'.

* cus-theme.el (customize-create-theme): Delete overlays after
erasing.  If given a THEME arg, display only the faces of that arg
instead of custom-theme--listed-faces.
(custom-theme-variable-menu, custom-theme-variable-action)
(custom-variable-reset-theme, custom-theme-delete-variable): Deleted.
(custom-theme-add-variable, custom-theme-add-face): Apply value
from the theme settings, instead of the current value.
(custom-theme-add-var-1, custom-theme-add-face-1): New functions.
(custom-theme-visit-theme): Allow calling outside theme buffers.
(custom-theme-merge-theme): Don't enable the theme when merging.
(custom-theme-write-variables, custom-theme-write-faces): Use the
:shown-value properties to save buffer values, not global ones.
(customize-themes): Display a warning about user customizations.

* cus-edit.el (custom-variable-value-create)
(custom-face-value-create): Obey new special properties
:shown-value and :inhibit-magic.

3 files changed, 237 insertions, 241 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 4097b914223..931ee696482 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,23 @@
+2010-10-16  Chong Yidong  <cyd@stupidchicken.com>
+
+        * cus-theme.el (customize-create-theme): Delete overlays after
+        erasing.  If given a THEME arg, display only the faces of that arg
+        instead of custom-theme--listed-faces.
+        (custom-theme-variable-menu, custom-theme-variable-action)
+        (custom-variable-reset-theme, custom-theme-delete-variable): Deleted.
+        (custom-theme-add-variable, custom-theme-add-face): Apply value
+        from the theme settings, instead of the current value.
+        (custom-theme-add-var-1, custom-theme-add-face-1): New functions.
+        (custom-theme-visit-theme): Allow calling outside theme buffers.
+        (custom-theme-merge-theme): Don't enable the theme when merging.
+        (custom-theme-write-variables, custom-theme-write-faces): Use the
+        :shown-value properties to save buffer values, not global ones.
+        (customize-themes): Display a warning about user customizations.
+
+        * cus-edit.el (custom-variable-value-create)
+        (custom-face-value-create): Obey new special properties
+        :shown-value and :inhibit-magic.
+
 2010-10-15  Michael Albinus  <michael.albinus@gmx.de>
 
         * net/tramp-sh.el (tramp-open-connection-setup-interactive-shell):
diff --git a/lisp/cus-edit.el b/lisp/cus-edit.el
index f7090bc322f..793b5cccedf 100644
--- a/lisp/cus-edit.el
+++ b/lisp/cus-edit.el
@@ -2460,7 +2460,13 @@ The following properties have special meanings for this widget:
 :custom-form should be a symbol describing how to display and
   edit the variable---either `edit' (using edit widgets),
   `lisp' (as a Lisp sexp), or `mismatch' (should not happen);
-  if nil, use the return value of `custom-variable-default-form'."
+  if nil, use the return value of `custom-variable-default-form'.
+
+:shown-value, if non-nil, should be a list whose `car' is the
+  variable value to display in place of the current value.
+
+:inhibit-magic, if non-nil, inhibits creating the magic
+  custom-state widget."
   :format "%v"
   :help-echo "Set or reset this variable."
   :documentation-property #'custom-variable-documentation
@@ -2512,9 +2518,12 @@ try matching its doc string against `custom-guess-doc-alist'."
          (get (or (get symbol 'custom-get) 'default-value))
          (prefix (widget-get widget :custom-prefix))
          (last (widget-get widget :custom-last))
-         (value (if (default-boundp symbol)
-                    (funcall get symbol)
-                  (widget-get conv :value)))
+         (value (let ((shown-value (widget-get widget :shown-value)))
+                  (cond (shown-value
+                         (car shown-value))
+                        ((default-boundp symbol)
+                         (funcall get symbol))
+                        (t (widget-get conv :value)))))
          (state (or (widget-get widget :custom-state)
                     (if (memq (custom-variable-state symbol value)
                               (widget-get widget :hidden-states))
@@ -2622,10 +2631,11 @@ try matching its doc string against `custom-guess-doc-alist'."
       (unless (eq (preceding-char) ?\n)
         (widget-insert "\n"))
       ;; Create the magic button.
-      (let ((magic (widget-create-child-and-convert
-                    widget 'custom-magic nil)))
-        (widget-put widget :custom-magic magic)
-        (push magic buttons))
+      (unless (widget-get widget :inhibit-magic)
+        (let ((magic (widget-create-child-and-convert
+                      widget 'custom-magic nil)))
+          (widget-put widget :custom-magic magic)
+          (push magic buttons)))
       (widget-put widget :buttons buttons)
       ;; Insert documentation.
       (widget-put widget :documentation-indent 3)
@@ -3281,12 +3291,17 @@ The following properties have special meanings for this widget:
   Lisp sexp), or `mismatch' (should not happen); if nil, use
   the return value of `custom-face-default-form'.
 
-:display-style, if non-nil, should be a symbol describing the
-  style of display to use.  If the value is `concise', a more
-  concise interface is shown.
+:display-style, if non-nil, describes the style of display to
+  use.  If the value is `concise', a neater interface is shown.
+
+:sample-indent, if non-nil, is the number of columns to which to
+  indent the face sample (an integer).
 
-:sample-indent, if non-nil, should be an integer; this is the
-number of columns to which to indent the face sample."
+:shown-value, if non-nil, is the face spec to display as the value
+  of the widget, instead of the current face spec.
+
+:inhibit-magic, if non-nil, inhibits creating the magic
+  custom-state widget."
   :sample-face 'custom-face-tag
   :help-echo "Set or reset this face."
   :documentation-property #'face-doc-string
@@ -3429,14 +3444,19 @@ WIDGET should be a `custom-face' widget."
              (indent-to-column sample-indent)))
       (push (widget-create-child-and-convert
              widget 'item
-             :format "[%{%t%}]" :sample-face symbol :tag "sample")
+             :format "[%{%t%}]"
+             :sample-face (let ((spec (widget-get widget :shown-value)))
+                            (if spec (face-spec-choose spec) symbol))
+             :tag "sample")
             buttons)
-      ;; Magic.
       (insert "\n")
-      (let ((magic (widget-create-child-and-convert
-                    widget 'custom-magic nil)))
-        (widget-put widget :custom-magic magic)
-        (push magic buttons))
+
+      ;; Magic.
+      (unless (widget-get widget :inhibit-magic)
+        (let ((magic (widget-create-child-and-convert
+                      widget 'custom-magic nil)))
+          (widget-put widget :custom-magic magic)
+          (push magic buttons)))
 
       ;; Update buttons.
       (widget-put widget :buttons buttons)
@@ -3465,7 +3485,8 @@ WIDGET should be a `custom-face' widget."
         (unless (widget-get widget :custom-form)
           (widget-put widget :custom-form custom-face-default-form))
 
-        (let* ((spec (custom-face-get-current-spec symbol))
+        (let* ((spec (or (widget-get widget :shown-value)
+                         (custom-face-get-current-spec symbol)))
                (form (widget-get widget :custom-form))
                (indent (widget-get widget :indent))
                face-alist face-entry spec-default spec-match editor)
diff --git a/lisp/cus-theme.el b/lisp/cus-theme.el
index 197d9787d9a..241dd6cc069 100644
--- a/lisp/cus-theme.el
+++ b/lisp/cus-theme.el
@@ -79,12 +79,14 @@ Do not call this mode function yourself.  It is meant for internal use."
 (defun customize-create-theme (&optional theme buffer)
   "Create or edit a custom theme.
 THEME, if non-nil, should be an existing theme to edit.
-BUFFER, if non-nil, should be a buffer to use."
+BUFFER, if non-nil, should be a buffer to use; the default is
+named *Custom Theme*."
   (interactive)
   (switch-to-buffer (get-buffer-create (or buffer "*Custom Theme*")))
-  ;; Save current faces
   (let ((inhibit-read-only t))
-    (erase-buffer))
+    (erase-buffer)
+    (dolist (ov (overlays-in (point-min) (point-max)))
+      (delete-overlay ov)))
   (custom-new-theme-mode)
   (make-local-variable 'custom-theme-name)
   (set (make-local-variable 'custom-theme--save-name) theme)
@@ -121,50 +123,59 @@ BUFFER, if non-nil, should be a buffer to use."
   (widget-create 'push-button
                  :notify (function custom-theme-write)
                  " Save Theme ")
-  ;; Face widgets
-  (widget-insert "\n\n  Theme faces:\n")
-  (let (widget)
-    (dolist (face custom-theme--listed-faces)
-      (widget-insert "  ")
-      (setq widget (widget-create 'custom-face
-                                  :documentation-shown t
-                                  :tag (custom-unlispify-tag-name face)
-                                  :value face
-                                  :display-style 'concise
-                                  :custom-state 'hidden
-                                  :sample-indent 34))
-      (custom-magic-reset widget)
-      (push (cons face widget) custom-theme-faces)))
-  (insert " ")
-  (setq custom-theme-insert-face-marker (point-marker))
-  (insert " ")
-  (widget-create 'push-button
-                 :tag "Insert Additional Face"
-                 :help-echo "Add another face to this theme."
-                 :follow-link 'mouse-face
-                 :button-face 'custom-link
-                 :mouse-face 'highlight
-                 :pressed-face 'highlight
-                 :action (lambda (widget &optional event)
-                           (call-interactively 'custom-theme-add-face)))
-  (widget-insert "\n\n  Theme variables:\n ")
-  (setq custom-theme-insert-variable-marker (point-marker))
-  (widget-insert ?\s)
-  (widget-create 'push-button
-                 :tag "Insert Variable"
-                 :help-echo "Add another variable to this theme."
-                 :follow-link 'mouse-face
-                 :button-face 'custom-link
-                 :mouse-face 'highlight
-                 :pressed-face 'highlight
-                 :action (lambda (widget &optional event)
-                           (call-interactively 'custom-theme-add-variable)))
-  (widget-insert ?\n)
-  (if theme
-      (custom-theme-merge-theme theme))
-  (widget-setup)
-  (goto-char (point-min))
-  (message ""))
+
+  (let (vars values faces face-specs)
+
+    ;; Load the theme settings.
+    (when theme
+      (load-theme theme t)
+      (dolist (setting (get theme 'theme-settings))
+        (if (eq (car setting) 'theme-value)
+            (progn (push (nth 1 setting) vars)
+                   (push (nth 3 setting) values))
+          (push (nth 1 setting) faces)
+          (push (nth 3 setting) face-specs))))
+
+    ;; If THEME is non-nil, insert all of that theme's faces.
+    ;; Otherwise, insert those in `custom-theme--listed-faces'.
+    (widget-insert "\n\n  Theme faces:\n ")
+    (if theme
+        (while faces
+          (custom-theme-add-face-1 (pop faces) (pop face-specs)))
+      (dolist (face custom-theme--listed-faces)
+        (custom-theme-add-face-1 face nil)))
+    (setq custom-theme-insert-face-marker (point-marker))
+    (widget-insert " ")
+    (widget-create 'push-button
+                   :tag "Insert Additional Face"
+                   :help-echo "Add another face to this theme."
+                   :follow-link 'mouse-face
+                   :button-face 'custom-link
+                   :mouse-face 'highlight
+                   :pressed-face 'highlight
+                   :action (lambda (widget &optional event)
+                             (call-interactively 'custom-theme-add-face)))
+
+    ;; If THEME is non-nil, insert all of that theme's variables.
+    (widget-insert "\n\n  Theme variables:\n ")
+    (if theme
+        (while vars
+          (custom-theme-add-var-1 (pop vars) (pop values))))
+    (setq custom-theme-insert-variable-marker (point-marker))
+    (widget-insert " ")
+    (widget-create 'push-button
+                   :tag "Insert Variable"
+                   :help-echo "Add another variable to this theme."
+                   :follow-link 'mouse-face
+                   :button-face 'custom-link
+                   :mouse-face 'highlight
+                   :pressed-face 'highlight
+                   :action (lambda (widget &optional event)
+                             (call-interactively 'custom-theme-add-variable)))
+    (widget-insert ?\n)
+    (widget-setup)
+    (goto-char (point-min))
+    (message "")))
 
 (defun custom-theme-revert (ignore-auto noconfirm)
   (when (or noconfirm (y-or-n-p "Discard current changes? "))
@@ -172,177 +183,119 @@ BUFFER, if non-nil, should be a buffer to use."
 
 ;;; Theme variables
 
-(defun custom-theme-add-variable (symbol)
-  (interactive "vVariable name: ")
-  (cond ((assq symbol custom-theme-variables)
-         (message "%s is already in the theme" (symbol-name symbol)))
-        ((not (boundp symbol))
-         (message "%s is not defined as a variable" (symbol-name symbol)))
-        ((eq symbol 'custom-enabled-themes)
-         (message "Custom theme cannot contain `custom-enabled-themes'"))
-        (t
-         (save-excursion
-           (goto-char custom-theme-insert-variable-marker)
-           (widget-insert " ")
-           (let ((widget (widget-create 'custom-variable
-                                        :tag (custom-unlispify-tag-name symbol)
-                                        :custom-level 0
-                                        :action 'custom-theme-variable-action
-                                        :custom-state 'unknown
-                                        :value symbol)))
-             (push (cons symbol widget) custom-theme-variables)
-             (custom-magic-reset widget))
-           (widget-insert " ")
-           (move-marker custom-theme-insert-variable-marker (point))
-           (widget-setup)))))
-
-(defvar custom-theme-variable-menu
-  `(("Reset to Current" custom-redraw
-     (lambda (widget)
-       (and (boundp (widget-value widget))
-            (memq (widget-get widget :custom-state)
-                  '(themed modified changed)))))
-    ("Reset to Theme Value" custom-variable-reset-theme
-     (lambda (widget)
-       (let ((theme  (intern (widget-value custom-theme-name)))
-             (symbol (widget-value widget))
-             found)
-         (and (custom-theme-p theme)
-              (dolist (setting (get theme 'theme-settings) found)
-                (if (and (eq (cadr setting) symbol)
-                         (eq (car  setting) 'theme-value))
-                    (setq found t)))))))
-    ("---" ignore ignore)
-    ("Delete" custom-theme-delete-variable nil))
-  "Alist of actions for the `custom-variable' widget in Custom Theme Mode.
-See the documentation for `custom-variable'.")
-
-(defun custom-theme-variable-action (widget &optional event)
-  "Show the Custom Theme Mode menu for a `custom-variable' widget.
-Optional EVENT is the location for the menu."
-  (let ((custom-variable-menu custom-theme-variable-menu))
-    (custom-variable-action widget event)))
-
-(defun custom-variable-reset-theme (widget)
-  "Reset WIDGET to its value for the currently edited theme."
-  (let ((theme  (intern (widget-value custom-theme-name)))
-        (symbol (widget-value widget))
-        found)
-    (dolist (setting (get theme 'theme-settings))
-      (if (and (eq (cadr setting) symbol)
-               (eq (car  setting) 'theme-value))
-          (setq found setting)))
-    (widget-value-set (car (widget-get widget :children))
-                      (nth 3 found)))
-  (widget-put widget :custom-state 'themed)
-  (custom-redraw-magic widget)
-  (widget-setup))
-
-(defun custom-theme-delete-variable (widget)
-  (setq custom-theme-variables
-        (assq-delete-all (widget-value widget) custom-theme-variables))
-  (widget-delete widget))
+(defun custom-theme-add-variable (var value)
+  "Add a widget for VAR (a symbol) to the *New Custom Theme* buffer.
+VALUE should be a value to which to set the widget; when called
+interactively, this defaults to the current value of VAR."
+  (interactive
+   (let ((v (read-variable "Variable name: ")))
+     (list v (symbol-value v))))
+  (let ((var-and-widget (assq var custom-theme-faces)))
+    (cond ((null var-and-widget)
+           ;; If VAR is not yet in the buffer, add it.
+           (save-excursion
+             (goto-char custom-theme-insert-variable-marker)
+             (custom-theme-add-var-1 var value)
+             (move-marker custom-theme-insert-variable-marker (point))
+             (widget-setup)))
+          ;; Otherwise, alter that var widget.
+          (t
+           (let ((widget (cdr var-and-widget)))
+             (widget-put widget :shown-value (list value))
+             (custom-redraw widget))))))
+
+(defun custom-theme-add-var-1 (symbol val)
+  (widget-insert " ")
+  (push (cons symbol
+              (widget-create 'custom-variable
+                             :tag (custom-unlispify-tag-name symbol)
+                             :value symbol
+                             :shown-value (list val)
+                             :notify 'ignore
+                             :custom-level 0
+                             :custom-state 'hidden
+                             :inhibit-magic t))
+        custom-theme-variables)
+  (widget-insert " "))
 
 ;;; Theme faces
 
-(defun custom-theme-add-face (symbol)
-  (interactive (list (read-face-name "Face name" nil nil)))
-  (cond ((assq symbol custom-theme-faces)
-         (message "%s is already in the theme" (symbol-name symbol)))
-        ((not (facep symbol))
-         (message "%s is not defined as a face" (symbol-name symbol)))
-        (t
-         (save-excursion
-           (goto-char custom-theme-insert-face-marker)
-           (widget-insert " ")
-           (let ((widget (widget-create 'custom-face
-                                        :tag (custom-unlispify-tag-name symbol)
-                                        :custom-level 0
-                                        :action 'custom-theme-face-action
-                                        :custom-state 'unknown
-                                        :display-style 'concise
-                                        :sample-indent 34
-                                        :value symbol)))
-             (push (cons symbol widget) custom-theme-faces)
-             (custom-magic-reset widget)
-             (widget-insert " ")
+(defun custom-theme-add-face (face &optional spec)
+  "Add a widget for FACE (a symbol) to the *New Custom Theme* buffer.
+SPEC, if non-nil, should be a face spec to which to set the widget."
+  (interactive (list (read-face-name "Face name" nil nil) nil))
+  (unless (or (facep face) spec)
+    (error "`%s' has no face definition" face))
+  (let ((face-and-widget (assq face custom-theme-faces)))
+    (cond ((null face-and-widget)
+           ;; If FACE is not yet in the buffer, add it.
+           (save-excursion
+             (goto-char custom-theme-insert-face-marker)
+             (custom-theme-add-face-1 face spec)
              (move-marker custom-theme-insert-face-marker (point))
-             (widget-setup))))))
-
-(defvar custom-theme-face-menu
-  `(("Reset to Theme Value" custom-face-reset-theme
-     (lambda (widget)
-       (let ((theme  (intern (widget-value custom-theme-name)))
-             (symbol (widget-value widget))
-             found)
-         (and (custom-theme-p theme)
-              (dolist (setting (get theme 'theme-settings) found)
-                (if (and (eq (cadr setting) symbol)
-                         (eq (car  setting) 'theme-face))
-                    (setq found t)))))))
-    ("---" ignore ignore)
-    ("Delete" custom-theme-delete-face nil))
-  "Alist of actions for the `custom-variable' widget in Custom Theme Mode.
-See the documentation for `custom-variable'.")
-
-(defun custom-theme-face-action (widget &optional event)
-  "Show the Custom Theme Mode menu for a `custom-face' widget.
-Optional EVENT is the location for the menu."
-  (let ((custom-face-menu custom-theme-face-menu))
-    (custom-face-action widget event)))
-
-(defun custom-face-reset-theme (widget)
-  "Reset WIDGET to its value for the currently edited theme."
-  (let ((theme  (intern (widget-value custom-theme-name)))
-        (symbol (widget-value widget))
-        found)
-    (dolist (setting (get theme 'theme-settings))
-      (if (and (eq (cadr setting) symbol)
-               (eq (car  setting) 'theme-face))
-          (setq found setting)))
-    (widget-value-set (car (widget-get widget :children))
-                      (nth 3 found)))
-  (widget-put widget :custom-state 'themed)
-  (custom-redraw-magic widget)
-  (widget-setup))
-
-(defun custom-theme-delete-face (widget)
-  (setq custom-theme-faces
-        (assq-delete-all (widget-value widget) custom-theme-faces))
-  (widget-delete widget))
+             (widget-setup)))
+          ;; Otherwise, if SPEC is supplied, alter that face widget.
+          (spec
+           (let ((widget (cdr face-and-widget)))
+             (widget-put widget :shown-value spec)
+             (custom-redraw widget)))
+          ((called-interactively-p 'interactive)
+           (error "`%s' is already present" face)))))
+
+(defun custom-theme-add-face-1 (symbol spec)
+  (widget-insert " ")
+  (push (cons symbol
+              (widget-create 'custom-face
+                             :tag (custom-unlispify-tag-name symbol)
+                             :documentation-shown t
+                             :value symbol
+                             :custom-state 'hidden
+                             :display-style 'concise
+                             :shown-value spec
+                             :inhibit-magic t
+                             :sample-indent 34))
+        custom-theme-faces)
+  (widget-insert " "))
 
 ;;; Reading and writing
 
-(defun custom-theme-visit-theme ()
-  (interactive)
-  (when (and (y-or-n-p "Discard current changes? ")
-             (progn (revert-buffer) t))
-    (let ((theme (call-interactively 'custom-theme-merge-theme)))
-      (unless (eq theme 'user)
-        (widget-value-set custom-theme-name (symbol-name theme)))
-      (widget-value-set custom-theme-description
-                        (or (get theme 'theme-documentation)
-                            (format-time-string "Created %Y-%m-%d.")))
-      (widget-setup))))
+(defun custom-theme-visit-theme (theme)
+  "Load the custom theme THEME's settings into the current buffer."
+  (interactive
+   (list
+    (intern (completing-read "Find custom theme: "
+                             (mapcar 'symbol-name
+                                     (custom-available-themes))))))
+  (unless (custom-theme-name-valid-p theme)
+    (error "No valid theme named `%s'" theme))
+  (cond ((not (eq major-mode 'custom-new-theme-mode))
+         (customize-create-theme theme))
+        ((y-or-n-p "Discard current changes? ")
+         (setq custom-theme--save-name theme)
+         (custom-theme-revert nil t))))
 
 (defun custom-theme-merge-theme (theme)
+  "Merge the custom theme THEME's settings into the current buffer."
   (interactive
    (list
     (intern (completing-read "Merge custom theme: "
                              (mapcar 'symbol-name
                                      (custom-available-themes))))))
-  (unless (custom-theme-name-valid-p theme)
-    (error "Invalid theme name `%s'" theme))
-  (load-theme theme)
-  (let ((settings (get theme 'theme-settings)))
+  (unless (eq theme 'user)
+    (unless (custom-theme-name-valid-p theme)
+      (error "Invalid theme name `%s'" theme))
+    (load-theme theme t))
+  (let ((settings (reverse (get theme 'theme-settings))))
     (dolist (setting settings)
-      (if (eq (car setting) 'theme-value)
-          (custom-theme-add-variable (cadr setting))
-        (custom-theme-add-face (cadr setting)))))
-  (disable-theme theme)
+      (funcall (if (eq (car setting) 'theme-value)
+                   'custom-theme-add-variable
+                 'custom-theme-add-face)
+               (nth 1 setting)
+               (nth 3 setting))))
   theme)
 
 (defun custom-theme-write (&rest ignore)
+  "Write the current custom theme to its theme file."
   (interactive)
   (let* ((name (widget-value custom-theme-name))
          (doc (widget-value custom-theme-description))
@@ -395,11 +348,12 @@ It includes all variables in list VARS."
       (princ "\n")
       (dolist (spec vars)
         (let* ((symbol (car spec))
-               (child (car-safe (widget-get (cdr spec) :children)))
+               (widget (cdr spec))
+               (child (car-safe (widget-get widget :children)))
                (value (if child
                           (widget-value child)
-                        ;; For hidden widgets, use the standard value
-                        (get symbol 'standard-value))))
+                        ;; Child is null if the widget is closed (hidden).
+                        (car (widget-get widget :shown-value)))))
           (when (boundp symbol)
             (unless (bolp)
               (princ "\n"))
@@ -426,30 +380,18 @@ It includes all faces in list FACES."
       (dolist (spec faces)
         (let* ((symbol (car spec))
                (widget (cdr spec))
-               (child  (car-safe (widget-get widget :children)))
-               (state  (if child
-                           (widget-get widget :custom-state)
-                         (custom-face-state symbol)))
                (value
-                (cond ((eq state 'standard)
-                       nil) ; do nothing
-                      (child
-                       (custom-face-widget-to-spec widget))
-                      (t
-                       ;; Widget is closed (hidden), but the face has
-                       ;; a non-standard value.  Try to extract that
-                       ;; value and save it.
-                       (custom-face-get-current-spec symbol)))))
+                (if (car-safe (widget-get widget :children))
+                    (custom-face-widget-to-spec widget)
+                  ;; Child is null if the widget is closed (hidden).
+                  (widget-get widget :shown-value))))
           (when (and (facep symbol) value)
-            (if (bolp)
-                (princ " '(")
-              (princ "\n '("))
+            (princ (if (bolp) " '(" "\n '("))
             (prin1 symbol)
             (princ " ")
             (prin1 value)
             (princ ")"))))
-      (if (bolp)
-          (princ " "))
+      (if (bolp) (princ " "))
       (princ ")")
       (unless (looking-at "\n")
         (princ "\n")))))
@@ -587,6 +529,19 @@ Theme files are named *-theme.el in `"))
                  :action (lambda (widget &rest ignore)
                            (describe-variable 'load-path)))
   (widget-insert "'.\n\n")
+
+  ;; If the user has made customizations, display a warning and
+  ;; provide buttons to disable or convert them.
+  (let ((user-settings (get 'user 'theme-settings)))
+    (unless (or (null user-settings)
+                (and (null (cdr user-settings))
+                     (eq (caar user-settings) 'theme-value)
+                     (eq (cadr (car user-settings)) 'custom-enabled-themes)))
+      (widget-insert "Note: Your custom settings take precedence over theme settings.\n\n")
+      ;; FIXME: Provide some way to painlessly disable or migrate
+      ;; these settings.
+      ))
+
   (widget-create 'push-button
                  :tag " Save Theme Settings "
                  :help-echo "Save the selected themes for future sessions."