1 files changed, 1 insertions, 1 deletions

diff --git a/lisp/cus-face.el b/lisp/cus-face.el
index 2b32ce3f522..b465aada7ae 100644
--- a/lisp/cus-face.el
+++ b/lisp/cus-face.el
@@ -56,7 +56,7 @@
         (if (memq window-system '(x w32))
             (make-face-x-resource-internal face))))
     (when (and doc (null (face-documentation face)))
-      (set-face-documentation face doc))
+      (set-face-documentation face (purecopy doc)))
     (custom-handle-all-keywords face args 'custom-face)
     (run-hooks 'custom-define-hook))
   face)