diff --git a/core/core-ui.el b/core/core-ui.el
index f4fb397b5..56e5f2559 100644
--- a/core/core-ui.el
+++ b/core/core-ui.el
@@ -330,7 +330,7 @@ DEFAULT is non-nil, set the default mode-line for all buffers."
   "Show whitespace-mode when file has an `indent-tabs-mode' that is different
 from the default."
   (unless (or (eq indent-tabs-mode (default-value 'indent-tabs-mode))
-              (eq major-mode fundamental-mode)
+              (eq major-mode 'fundamental-mode)
               (derived-mode-p 'special-mode))
     (require 'whitespace)
     (set (make-local-variable 'whitespace-style)