diff --git a/lisp/org-agenda.el b/lisp/org-agenda.el
index b02b2f7c0..088f17645 100644
--- a/lisp/org-agenda.el
+++ b/lisp/org-agenda.el
@@ -2006,7 +2006,7 @@ If STRING is non-nil, the text property will be fetched from position 0
 in that string.  If STRING is nil, it will be fetched from the beginning
 of the current line."
   (org-with-gensyms (marker)
-    `(let ((,marker (get-text-property (if string 0 (point-at-bol))
+    `(let ((,marker (get-text-property (if ,string 0 (point-at-bol))
 				       'org-hd-marker ,string)))
        (with-current-buffer (marker-buffer ,marker)
 	 (save-excursion