diff --git a/demos/droppable/photo-manager.html b/demos/droppable/photo-manager.html
index 2957f91c4..9b4132c33 100644
--- a/demos/droppable/photo-manager.html
+++ b/demos/droppable/photo-manager.html
@@ -12,6 +12,7 @@
 	<script src="../../ui/draggable.js"></script>
 	<script src="../../ui/droppable.js"></script>
 	<script src="../../ui/resizable.js"></script>
+	<script src="../../ui/button.js"></script>
 	<script src="../../ui/dialog.js"></script>
 	<link rel="stylesheet" href="../demos.css">
 	<style>