diff --git a/src/utils.scm b/src/utils.scm
index 6100dcd..f10e56b 100644
--- a/src/utils.scm
+++ b/src/utils.scm
@@ -280,7 +280,7 @@
   (or (window-focused? dpy window)
       (any (lambda (child)
 	     (window-contains-focus? dpy child))
-	   (window-children dpy window))))
+	   (or (window-children dpy window) '()))))
 
 (define (take-focus dpy window time)
   ;; implements the TAKE_FOCUS protocol