(frame-background-mode): Define a :set function

to update the background mode of existing frames.

diff --git a/lisp/faces.el b/lisp/faces.el
index 58b984ce876057fe3288b9670c321d88cc50b086..2e3529fabf36458b2acd6790a03dd39d1d61e060 100644 (file)
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1432,6 +1432,10 @@ Set this to the symbol dark if your background color is dark, light if
 your background is light, or nil (default) if you want Emacs to
 examine the brightness for you."
   :group 'faces
+  :set #'(lambda (var value)
+          (set var value)
+          (mapcar 'frame-set-background-mode (frame-list)))
+  :initialize 'custom-initialize-changed
   :type '(choice (choice-item dark) 
                 (choice-item light)
                 (choice-item :tag "default" nil)))