Make certain to quote the key when building the query string.

@@ -135,7 +135,7 @@ define(function(require) {
                     var checkedItems = [];
                     impl.get('items').each(function(item) {
                         if (item.get('checked')) {
-                            checkedItems.push(item.get('key'));
+                            checkedItems.push(impl.queryValue ? impl.queryValue(item) : item.get('key'));
                         }
                     });
                     if (checkedItems.length) {