diff --git a/src/board.js b/src/board.js
index 532312f2f9..02ee3414bb 100644
--- a/src/board.js
+++ b/src/board.js
@@ -34,6 +34,7 @@
 
             this.context = context;
             this.actions = [];
+            this.containers = [];
             this.state_widgets = [];
             this.el = jQuery('<div/>', {
                 'class': 'board'