diff --git a/lisp/hi-lock.el b/lisp/hi-lock.el
index de258935e1..9173b66b7f 100644
--- a/lisp/hi-lock.el
+++ b/lisp/hi-lock.el
@@ -625,7 +645,12 @@ hi-lock-unface-buffer
       ;; calls font-lock-set-defaults).  This is yet-another bug in
       ;; font-lock-add/remove-keywords, which we circumvent here by
       ;; testing `font-lock-fontified' (bug#19796).
-      (if font-lock-fontified (font-lock-remove-keywords nil (list keyword)))
+      (when font-lock-fontified
+        (font-lock-remove-keywords nil (list keyword))
+        (dolist (k font-lock-keywords)
+          (when (and (consp k) (consp (car k)) (eq (caar k) 'closure)
+                     (equal (car keyword) (cdr (assq 'regexp (cadr (car k))))))
+            (font-lock-remove-keywords nil (list k)))))
       (setq hi-lock-interactive-patterns
             (delq keyword hi-lock-interactive-patterns))
       (remove-overlays
@@ -728,7 +753,13 @@ hi-lock-set-pattern
       (push pattern hi-lock-interactive-patterns)
       (if (and font-lock-mode (font-lock-specified-p major-mode))
 	  (progn
-	    (font-lock-add-keywords nil (list pattern) t)
+	    (font-lock-add-keywords
+             nil (list (cons
+                        (lambda (limit)
+                          (let ((case-fold-search case-fold))
+                            (re-search-forward (car pattern) limit t)))
+                        (cdr pattern)))
+             t)
 	    (font-lock-flush))
         (let* ((range-min (- (point) (/ hi-lock-highlight-range 2)))
                (range-max (+ (point) (/ hi-lock-highlight-range 2)))