diff --git a/lisp/descr-text.el b/lisp/descr-text.el
index 525e06e4a37..5ef3a2990d8 100644
--- a/lisp/descr-text.el
+++ b/lisp/descr-text.el
@@ -56,6 +56,7 @@ if that value is non-nil."
 	mode-name "Describe-Text")
   (use-local-map describe-text-mode-map)
   (widget-setup)
+  (add-hook 'change-major-mode-hook 'font-lock-defontify nil t)
   (run-hooks 'describe-text-mode-hook))
 
 ;;; Describe-Text Utilities.